Clear answers when your heating isn’t playing nicely.
Plain-English boiler and central-heating guidance for UK homeowners and landlords. Properly researched, safety checked and written for people—not engineers.
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Choose the closest subject. Each guide explains the useful homeowner checks, the likely next step and where qualified help is needed.
Boiler problems
No heating, no hot water, leaks, pressure changes and unfamiliar noises.
Fault codes
Plain-English explanations checked against the correct manufacturer information.
Heating & radiators
Cold patches, trapped air, controls and common circulation problems.
Servicing & safety
Annual servicing, gas safety, carbon monoxide and knowing when something is urgent.
Landlord guidance
Practical UK information about checks, records, access and heating responsibilities.
Replacement & costs
Understanding quotations, boiler types, warranties and the decisions behind the price.
Help by boiler manufacturer
We’re prioritising the boilers most commonly encountered in UK homes, while keeping every explanation model-specific and properly sourced.
Boiler help & advice
Six useful places to start. Search above, or choose a manufacturer, to see every matching guide.
Baxi 600 Combi 2 A.00.34 warning: outdoor temperature sensor expected but not detected
← Back to Boiler Help & Advice Baxi 600 Combi 2 A.00.34 warning: outdoor temperature sensor expected but not detected If your Baxi 600 Combi 2 shows A.00.34, Baxi defines the warning as “Out
Baxi 600 Combi 2 A.02.46 warning: device priority error
← Back to Boiler Help & Advice Baxi 600 Combi 2 A.02.46 warning: device priority error If your Baxi 600 Combi 2 shows A.02.46, Baxi describes the warning as “Device priority error”. The word
Baxi 600 Combi 2 A.02.54 code: OpenTherm bus power-supply error
← Back to Boiler Help & Advice Baxi 600 Combi 2 A.02.54 code: OpenTherm bus power-supply error Baxi’s current error-code table describes A.02.54 as “OpenTherm bus power supply error” for the
Baxi 600 Combi 2 A.02.55 warning: incorrect or missing serial number
← Back to Boiler Help & Advice Baxi 600 Combi 2 A.02.55 warning: incorrect or missing serial number If your Baxi 600 Combi 2 shows A.02.55, Baxi describes the warning as “Incorrect or missin
Baxi 600 Combi 2 E.00.04 fault code: return temperature sensor disconnected
← Back to Boiler Help & Advice Baxi 600 Combi 2 E.00.04 fault code: return temperature sensor disconnected Baxi’s official meaning for E.00.04 is “Return temperature sensor disconnected.” On
Baxi 600 Combi 2 E.00.20 fault code: flue-gas temperature sensor disconnected or below range
← Back to Boiler Help & Advice Baxi 600 Combi 2 E.00.20 fault code: flue-gas temperature sensor disconnected or below range If your Baxi 600 Combi 2 shows E.00.20, Baxi defines the fault as
Baxi 600 Combi 2 E.01.04 fault code: flame loss detected five times in 24 hours
← Back to Boiler Help & Advice Baxi 600 Combi 2 E.01.04 fault code: flame loss detected five times in 24 hours If your Baxi 600 Combi 2 shows E.01.04, Baxi’s current error-code table describ
Baxi 600 Combi 2 E.01.12 fault code: return temperature higher than flow temperature
← Back to Boiler Help & Advice The Baxi 600 Combi 2 E.01.12 fault code means “Temperature measured by return sensor greater than flow temperature.” That is the wording in Baxi’s current erro
Baxi 600 Combi 2 E.02.13 fault code: total boiler stoppage with antifreeze inactive
← Back to Boiler Help & Advice If your Baxi 600 Combi 2 displays E.02.13, Baxi defines the code as “Total stoppage of the boiler (antifreeze function not active)”. The boiler has stopped ope
Baxi 600 Combi 2 E.02.47 fault code: connection to external device unsuccessful
← Back to Boiler Help & Advice Baxi defines E.02.47 as “Connection to external device unsuccessful”. On a Baxi 600 Combi 2, the code means the boiler attempted a connection associated with a
Baxi 600 Combi 2 E.04.02 fault code: flow temperature sensor disconnected
← Back to Boiler Help & Advice Baxi 600 Combi 2 E.04.02 fault code: flow temperature sensor disconnected If your Baxi 600 Combi 2 shows E.04.02, Baxi’s current error-code table defines it as
Baxi 600 Combi 2 E.04.03 fault code: maximum flow temperature exceeded or sensor short circuit
← Back to Boiler Help & Advice Baxi 600 Combi 2 E.04.03 fault code: high flow temperature or sensor short circuit If your Baxi 600 Combi 2 shows E.04.03, Baxi gives two possible meanings: “M
Baxi 600 Combi 2 E.04.08 fault code: maximum safe temperature reached
← Back to Boiler Help & Advice Baxi’s current error-code table defines E.04.08 as “Maximum safe temperature value reached”. On a Baxi 600 Combi 2, it means the boiler has registered a temper
Baxi 600 Combi 2 E.04.10 fault code: burner failed to ignite after four attempts
← Back to Boiler Help & Advice If a Baxi 600 Combi 2 shows E.04.10, Baxi’s current error-code table says the burner failed to ignite after four attempts. The boiler has tried to start, has n
Baxi 600 Combi 2 E.04.18 fault code: flow temperature below minimum or sensor disconnected
← Back to Boiler Help & Advice Baxi 600 Combi 2 E.04.18 fault code: low flow temperature or sensor not connected Baxi lists E.04.18 on the Baxi 600 Combi 2 with two possible meanings: the fl
Baxi 600 Combi 2 E.04.18 fault code: low flow temperature or sensor disconnected
← Back to Boiler Help & Advice Baxi 600 Combi 2 E.04.18 fault code: low flow temperature or sensor disconnected Baxi lists E.04.18 for the current Combi & System 2 range as: “The flow temper
Baxi 600 Combi 2 E.04.23 fault code: internal communication stoppage
← Back to Boiler Help & Advice The Baxi 600 Combi 2 E.04.23 fault code means “Communication internal stoppage”. That is the wording in Baxi’s current error-code table for its Combi & System
Baxi 600 Combi 2 H.01.08 warning: heating flow temperature rising too quickly
← Back to Boiler Help & Advice Baxi 600 Combi 2 H.01.08 warning: heating flow temperature rising too quickly If your Baxi 600 Combi 2 displays H.01.08, Baxi defines the warning as “Flow temp
Baxi 600 Combi 2 H.01.18 warning: temporary no-water-circulation condition
← Back to Boiler Help & Advice Baxi 600 Combi 2 H.01.18 warning: temporary no-water-circulation condition If your Baxi 600 Combi 2 shows H.01.18, Baxi describes the warning as “No water circ
Baxi 600 Combi 2 H.02.07 code: permanently low heating-system pressure
← Back to Boiler Help & Advice If your Baxi 600 Combi 2 shows H.02.07, Baxi’s current error-code table defines it as “Low pressure in heating circuit (permanently).” The boiler has detected
Baxi 600 Combi 2 H.02.09 warning: partial boiler stoppage with antifreeze active
← Back to Boiler Help & Advice Baxi defines H.02.09 as “Partial stoppage of the boiler (antifreeze function active)”. On a Baxi 600 Combi 2, the warning means normal operation has been partl
Baxi 600 Combi 2 H.03.00 warning: no identification data for boiler safety device
← Back to Boiler Help & Advice Baxi 600 Combi 2 H.03.00 warning: no identification data for boiler safety device If your Baxi 600 Combi 2 displays H.03.00, Baxi defines the warning as “No id
Baxi 600 System 2 A.00.29 warning: solar temperature sensor short circuit or above range
← Back to Boiler Help & Advice The Baxi 600 System 2 A.00.29 warning means “Solar temperature sensor is either shorted or measures a temperature above range.” That is the full wording in Bax
Baxi 600 System 2 A.02.36 warning: functional device disconnected
← Back to Boiler Help & Advice The Baxi 600 System 2 A.02.36 warning means “Functional device disconnected.” That is the exact wording in Baxi’s current error-code table for its Combi & Syst
Baxi 600 System 2 A.02.45 warning: connection error
← Back to Boiler Help & Advice Baxi 600 System 2 A.02.45 warning: connection error A.02.45 on a Baxi 600 System 2 means “Connection error”. That is the current description in Baxi’s fault-co
Baxi 600 System 2 E.00.05 fault code: return temperature sensor short circuit
← Back to Boiler Help & Advice Baxi 600 System 2 E.00.05 fault code: return temperature sensor short circuit Baxi’s current error-code table defines E.00.05 as “Return temperature sensor sho
Baxi 600 System 2 E.00.16 fault code: hot-water cylinder sensor disconnected
← Back to Boiler Help & Advice If your Baxi 600 System 2 shows E.00.16, Baxi’s current error-code table defines it as “DHW tank temperature sensor not connected.” On a system-boiler installa
Baxi 600 System 2 E.00.17 fault code: hot-water tank temperature sensor short circuit
← Back to Boiler Help & Advice Baxi 600 System 2 E.00.17 fault code: hot-water tank temperature sensor short circuit If your Baxi 600 System 2 is showing E.00.17, the boiler has detected a p
Baxi 600 System 2 E.00.20 fault code: flue-gas temperature sensor disconnected or below range
← Back to Boiler Help & Advice If your Baxi 600 System 2 shows E.00.20, Baxi’s current wording is: “The flue gas temperature sensor is not connected or measured a temperature below the range
Baxi 600 System 2 E.01.04 fault code: flame loss five times in 24 hours
← Back to Boiler Help & Advice Baxi 600 System 2 E.01.04 fault code: flame loss five times in 24 hours Baxi’s official meaning for E.01.04 is “Flame loss detected five times in 24 hours.” On
Baxi 600 System 2 E.01.12 fault code: return temperature higher than flow temperature
← Back to Boiler Help & Advice Baxi 600 System 2 E.01.12 fault code: return temperature higher than flow temperature Baxi’s current error-code table defines E.01.12 as “Temperature measured
Baxi 600 System 2 E.01.17 fault code: no water circulation
← Back to Boiler Help & Advice Baxi 600 System 2 E.01.17 fault code: no water circulation If your Baxi 600 System 2 is showing E.01.17, the boiler has detected a permanent no-water-circulati
Baxi 600 System 2 E.02.13 fault code: total boiler stoppage with antifreeze inactive
← Back to Boiler Help & Advice Baxi 600 System 2 E.02.13 fault code: total stoppage with antifreeze inactive If your Baxi 600 System 2 is showing E.02.13, Baxi describes the fault as “Total
Baxi 600 System 2 E.02.35 fault code: critical safety device disconnected
← Back to Boiler Help & Advice Baxi 600 System 2 E.02.35 fault code: critical safety device disconnected If a Baxi 600 System 2 shows E.02.35, Baxi’s official description is “Critical safety
Baxi 600 System 2 E.02.47 fault code: external device connection unsuccessful
← Back to Boiler Help & Advice Baxi 600 System 2 E.02.47 fault code: external device connection unsuccessful Baxi’s current error-code table lists E.02.47 as “Connection to external device u
Baxi 600 System 2 E.04.01 fault code: flow temperature sensor short circuit
← Back to Boiler Help & Advice Baxi 600 System 2 E.04.01 fault code: flow temperature sensor short circuit If your Baxi 600 System 2 displays E.04.01, Baxi’s official description is “Flow te
Baxi 600 System 2 E.04.12 fault code: ignition failure during flame monitoring
← Back to Boiler Help & Advice Baxi’s current error-code table defines E.04.12 as “Ignition failure – flame monitoring”. On a Baxi 600 System 2, that means the boiler did not confirm t
Baxi 600 System 2 E.04.23 fault code: communication internal stoppage
← Back to Boiler Help & Advice Baxi 600 System 2 E.04.23 fault code: internal communication stoppage Baxi lists E.04.23 on the Baxi 600 System 2 as “Communication internal stoppage.” In simp
Baxi 600 System 2 H.00.81 code: room unit disconnected
← Back to Boiler Help & Advice Baxi 600 System 2 H.00.81 code: room unit disconnected Baxi describes H.00.81 as “Room unit disconnected” for its current Combi & System 2 boiler group, which
Baxi 600 System 2 H.01.00 warning: temporary gas-valve and boiler-control communication failure
← Back to Boiler Help & Advice Baxi 600 System 2 H.01.00 warning: temporary gas-valve and boiler-control communication failure If your Baxi 600 System 2 displays H.01.00, Baxi defines the wa
Baxi 600 System 2 H.01.05 code: maximum flow-return temperature difference
← Back to Boiler Help & Advice Baxi 600 System 2 H.01.05 code: maximum flow-return temperature difference Baxi describes H.01.05 as “Maximum temperature difference value between flow and ret
Baxi 600 System 2 H.01.08 code: heating flow temperature rising too quickly
← Back to Boiler Help & Advice If your Baxi 600 System 2 shows H.01.08, the boiler has detected that its heating flow temperature is increasing faster than expected. Baxi’s current wording i
Baxi 600 System 2 H.01.14 warning: maximum flow or return temperature reached
← Back to Boiler Help & Advice Baxi 600 System 2 H.01.14 warning: maximum flow or return temperature reached Baxi’s current error-code table lists H.01.14 as “Maximum flow or return temperat
Baxi 600 System 2 H.03.02 code: temporary flame loss
← Back to Boiler Help & Advice Baxi 600 System 2 H.03.02 code: temporary flame loss Baxi lists H.03.02 on the Baxi 600 System 2 as “Temporary flame loss.” This means the boiler detected that
Baxi 600 System 2 H.03.54 warning: temporary flame loss and low supply voltage shutdown
← Back to Boiler Help & Advice The Baxi 600 System 2 H.03.54 warning means “Temporary flame loss. Shutdown due to the power supply voltage being too low.” That complete wording comes from Ba
Baxi 800 Combi 2 A.02.37 warning: passive functional device disconnected
← Back to Boiler Help & Advice Baxi 800 Combi 2 A.02.37 warning: passive functional device disconnected If your Baxi 800 Combi 2 shows A.02.37, the boiler has detected that a passive functio
Baxi 800 Combi 2 A.02.54 warning: OpenTherm bus power-supply error
← Back to Boiler Help & Advice The Baxi 800 Combi 2 A.02.54 warning means “OpenTherm bus power supply error”. That is the wording in Baxi’s current error-code table for its Combi & System 2
Baxi 800 Combi 2 E.00.04 fault code: return temperature sensor disconnected
← Back to Boiler Help & Advice The Baxi 800 Combi 2 E.00.04 fault code means “Return temperature sensor disconnected.” That is the exact wording in Baxi’s current error-code table for its Co
Baxi 800 Combi 2 E.00.05 fault code: return temperature sensor short circuit
← Back to Boiler Help & Advice Baxi 800 Combi 2 E.00.05 fault code: return temperature sensor short circuit Baxi’s official meaning for E.00.05 is “Return temperature sensor short circuited.
Baxi 800 Combi 2 E.01.20 fault code: maximum flue-gas temperature reached
← Back to Boiler Help & Advice Baxi 800 Combi 2 E.01.20 fault code: maximum flue-gas temperature reached If your Baxi 800 Combi 2 displays E.01.20, Baxi defines it as “Maximum flue gas tempe
Baxi 800 Combi 2 E.02.17 fault code: permanent communication failure between gas valve and boiler control
← Back to Boiler Help & Advice Baxi 800 Combi 2 E.02.17 fault code: permanent communication failure between gas valve and boiler control If a Baxi 800 Combi 2 shows E.02.17, Baxi’s current e
Baxi 800 Combi 2 E.02.17 fault code: permanent gas-valve and PCB communication failure
← Back to Boiler Help & Advice Baxi 800 Combi 2 E.02.17 fault code: gas-valve and PCB communication failure If a Baxi 800 Combi 2 displays E.02.17, the boiler has detected a permanent commun
Baxi 800 Combi 2 E.02.39 fault code: minimum pressure not reached after automatic filling
← Back to Boiler Help & Advice Baxi 800 Combi 2 E.02.39 fault code: minimum pressure not reached after automatic filling If your Baxi 800 Combi 2 shows E.02.39, Baxi defines the code as “Min
Baxi 800 Combi 2 E.04.08 fault code: maximum safe temperature reached
← Back to Boiler Help & Advice If a Baxi 800 Combi 2 shows E.04.08, the boiler has recorded that its maximum safe temperature value has been reached. Baxi lists that wording for this model f
Baxi 800 Combi 2 E.04.10 fault code: burner failed to ignite after four attempts
← Back to Boiler Help & Advice Baxi defines E.04.10 as “Burner failed to ignite after 4 attempts” for its current Combi & System 2 boiler group. On a Baxi 800 Combi 2, the code means the app
Baxi 800 Combi 2 E.04.12 fault code: ignition failure and flame monitoring
← Back to Boiler Help & Advice Baxi describes E.04.12 on the Baxi 800 Combi 2 as “Ignition failure – flame monitoring.” The code means the boiler’s controls could not complete the expe
Baxi 800 Combi 2 E.04.13 fault code: fan impeller blocked or maximum speed exceeded
← Back to Boiler Help & Advice Baxi’s current error-code table gives two possibilities for E.04.13 on the Baxi 800 Combi 2: “Fan impeller blocked or maximum rpm exceeded.” The boiler has det
Baxi 800 Combi 2 E.04.17 fault code: gas-valve control-circuit fault
← Back to Boiler Help & Advice Baxi 800 Combi 2 E.04.17 fault code: gas-valve control-circuit fault Baxi’s current error-code table lists E.04.17 as “Fault in gas valve control circuit” for
Baxi 800 Combi 2 E.04.18 fault code: flow temperature below minimum or sensor not connected
← Back to Boiler Help & Advice Baxi’s current error-code table defines E.04.18 as: “The flow temperature is below the minimum temperature or the flow temperature sensor is not connected.” On
Baxi 800 Combi 2 H.00.81 warning: room unit disconnected
← Back to Boiler Help & Advice Baxi 800 Combi 2 H.00.81 warning: room unit disconnected If your Baxi 800 Combi 2 shows H.00.81, Baxi’s current error-code table defines the message as “Room u
Baxi 800 Combi 2 H.01.21 code: hot-water flow temperature rising too fast
← Back to Boiler Help & Advice Baxi 800 Combi 2 H.01.21 code: hot-water flow temperature rising too fast Baxi’s official description for H.01.21 is “Flow temperature increase during domestic
Baxi 800 Combi 2 H.01.21 warning: hot-water flow temperature rising too quickly
← Back to Boiler Help & Advice Baxi 800 Combi 2 H.01.21 warning: hot-water flow temperature rising too quickly If your Baxi 800 Combi 2 displays H.01.21, Baxi defines the warning as “Flow te
Baxi 800 Combi 2 H.02.70 code: external heat-recovery test failed
← Back to Boiler Help & Advice Baxi 800 Combi 2 H.02.70 code: external unit heat-recovery test failed Baxi lists H.02.70 for the Baxi 800 Combi 2 as “External unit heat recovery test failed.
Baxi 800 Combi 2 H.03.05 code: power-supply voltage too low
← Back to Boiler Help & Advice If your Baxi 800 Combi 2 shows H.03.05, Baxi’s current error-code table defines it as “Power supply voltage too low.” The boiler has detected that the electric
Baxi 800 Combi 2 H.03.05 warning: power-supply voltage too low
← Back to Boiler Help & Advice Baxi’s current error-code table defines H.03.05 as “Power supply voltage too low”. On a Baxi 800 Combi 2, the warning means the boiler has detected electrical
Baxi 800 System 2 A.00.28 warning: solar temperature sensor removed or below range
← Back to Boiler Help & Advice The Baxi 800 System 2 A.00.28 warning means “Solar temperature sensor is either removed or measures a temperature below range.” That complete wording appears i
Baxi 800 System 2 A.02.06 warning: low heating-circuit pressure
← Back to Boiler Help & Advice Seeing A.02.06 on a Baxi 800 System 2 means the boiler has detected low pressure in the sealed heating circuit. Baxi’s current error-code table gives the offic
Baxi 800 System 2 A.02.36 warning: functional device disconnected
← Back to Boiler Help & Advice Baxi 800 System 2 A.02.36 warning: functional device disconnected If your Baxi 800 System 2 shows A.02.36, Baxi defines the warning as “Functional device disco
Baxi 800 System 2 A.02.48 warning: unit-function configuration error
← Back to Boiler Help & Advice Baxi 800 System 2 A.02.48 warning: unit-function configuration error If your Baxi 800 System 2 displays A.02.48, Baxi describes the warning as “Unit function c
Baxi 800 System 2 A.02.49 warning: failed node initialisation
← Back to Boiler Help & Advice Baxi 800 System 2 A.02.49 warning: failed node initialisation A.02.49 on a Baxi 800 System 2 means “Failed node initialisation”. That is Baxi’s current descrip
Baxi 800 System 2 A.02.54 code: OpenTherm bus power-supply error
← Back to Boiler Help & Advice Baxi 800 System 2 A.02.54 code: OpenTherm bus power-supply error If your Baxi 800 System 2 shows A.02.54, Baxi’s official description is “OpenTherm bus power s
Baxi 800 System 2 A.02.76 warning: setting memory full for customisation
← Back to Boiler Help & Advice The Baxi 800 System 2 A.02.76 warning means “Internal memory reserved for full customisation of settings. No further changes can be made.” That is Baxi’s compl
Baxi 800 System 2 E.00.04 fault code: return temperature sensor disconnected
← Back to Boiler Help & Advice Baxi 800 System 2 E.00.04 fault code: return temperature sensor disconnected Baxi’s current error-code table lists E.00.04 as “Return temperature sensor discon
Baxi 800 System 2 E.00.16 fault code: hot-water tank temperature sensor not connected
← Back to Boiler Help & Advice Baxi 800 System 2 E.00.16 fault code: hot-water tank temperature sensor not connected E.00.16 on a Baxi 800 System 2 means “DHW tank temperature sensor not con
Baxi 800 System 2 E.00.17 fault code: hot-water cylinder sensor short circuit
← Back to Boiler Help & Advice If your Baxi 800 System 2 shows E.00.17, Baxi’s current error-code table defines it as “DHW tank temperature sensor short-circuited.” In this wording, “DHW tan
Baxi 800 System 2 E.00.21 fault code: flue-gas temperature sensor short circuit or above range
← Back to Boiler Help & Advice Baxi’s current error-code table defines E.00.21 as: “The flue gas temperature sensor has short-circuited or measured a temperature above the range.” On a Baxi
Baxi 800 System 2 E.01.12 fault code: return temperature greater than flow
← Back to Boiler Help & Advice Baxi 800 System 2 E.01.12 fault code: return temperature greater than flow Baxi’s official meaning for E.01.12 is “Temperature measured by return sensor greate
Baxi 800 System 2 E.01.17 fault code: no water circulation detected permanently
← Back to Boiler Help & Advice Baxi 800 System 2 E.01.17 fault code: no water circulation detected permanently If your Baxi 800 System 2 displays E.01.17, Baxi defines the fault as “No water
Baxi 800 System 2 E.01.20 fault code: maximum flue-gas temperature reached
← Back to Boiler Help & Advice Baxi defines E.01.20 as “Maximum flue gas temperature reached”. On a Baxi 800 System 2, that means the boiler has detected that its monitored flue-gas temperat
Baxi 800 System 2 E.02.13 fault code: total boiler stoppage with antifreeze inactive
← Back to Boiler Help & Advice Baxi 800 System 2 E.02.13 fault code: total boiler stoppage with antifreeze inactive Baxi lists E.02.13 as “Total stoppage of the boiler (antifreeze function n
Baxi 800 System 2 E.02.39 fault code: minimum pressure not reached after automatic filling
← Back to Boiler Help & Advice Baxi 800 System 2 E.02.39 fault code: minimum pressure not reached after automatic filling If your Baxi 800 System 2 displays E.02.39, Baxi’s official descript
Baxi 800 System 2 E.04.01 fault code: flow temperature sensor short circuit
← Back to Boiler Help & Advice Baxi 800 System 2 E.04.01 fault code: flow temperature sensor short circuit If your Baxi 800 System 2 displays E.04.01, Baxi defines the fault as “Flow tempera
Baxi 800 System 2 E.04.02 fault code: flow temperature sensor disconnected
← Back to Boiler Help & Advice Baxi 800 System 2 E.04.02 fault code: flow temperature sensor disconnected If your Baxi 800 System 2 shows E.04.02, Baxi’s official description is “Flow temper
Baxi 800 System 2 E.04.03 fault code: maximum flow temperature or sensor short circuit
← Back to Boiler Help & Advice Baxi 800 System 2 E.04.03 fault code: maximum flow temperature or sensor short circuit If your Baxi 800 System 2 displays E.04.03, Baxi defines the fault as “M
Baxi 800 System 2 E.04.13 fault code: fan impeller blocked or maximum speed exceeded
← Back to Boiler Help & Advice Baxi defines E.04.13 as “Fan impeller blocked or maximum rpm exceeded”. On a Baxi 800 System 2, the code presents two distinct possibilities: the boiler has de
Baxi 800 System 2 E.04.23 fault code: internal communication stoppage
← Back to Boiler Help & Advice Baxi 800 System 2 E.04.23 fault code: internal communication stoppage If your Baxi 800 System 2 is showing E.04.23, Baxi describes the fault as “Communication
Baxi 800 System 2 E.04.254 fault code: gas valve control circuit fault
← Back to Boiler Help & Advice Baxi 800 System 2 E.04.254 fault code: gas-valve control-circuit fault Baxi lists E.04.254 on the Baxi 800 System 2 as “Fault in gas valve control circuit.” Th
Baxi 800 System 2 H.00.42 code: pressure sensor open or faulty
← Back to Boiler Help & Advice Baxi 800 System 2 H.00.42 code: pressure sensor open or faulty Baxi’s current error-code table lists H.00.42 as “Pressure sensor open/faulty” for the Combi �
Baxi 800 System 2 H.01.00 code: temporary gas-valve and boiler PCB communication failure
← Back to Boiler Help & Advice If your Baxi 800 System 2 shows H.01.00, Baxi’s current error-code table defines it as “Temporary communication failure between gas valve and boiler PCB.” The
Baxi 800 System 2 H.01.05 warning: maximum temperature difference between flow and return reached
← Back to Boiler Help & Advice Baxi 800 System 2 H.01.05 warning: maximum temperature difference between flow and return reached Baxi describes H.01.05 as “Maximum temperature difference val
Baxi 800 System 2 H.02.07 warning: permanently low heating-circuit pressure
← Back to Boiler Help & Advice Baxi 800 System 2 H.02.07 warning: permanently low heating-circuit pressure If your Baxi 800 System 2 displays H.02.07, Baxi defines the warning as “Low pressu
Baxi 800 System 2 H.03.54 code: temporary flame loss with low supply voltage
← Back to Boiler Help & Advice Baxi 800 System 2 H.03.54 code: temporary flame loss with low supply voltage If your Baxi 800 System 2 is showing H.03.54, the official Baxi description is “Te
Baxi A.00.28 code: solar temperature sensor below range
← Back to Boiler Help & Advice The Baxi A.00.28 code means the solar temperature sensor is either removed or measures a temperature below range. Those are the two possibilities in Baxi’s cur
Baxi A.00.29 code: solar temperature sensor above range
← Back to Boiler Help & Advice The Baxi A.00.29 code means the solar temperature sensor is either shorted or measures a temperature above range. It is a sensor-related warning on compatible
Baxi A.00.34 code: outdoor temperature sensor expected but not detected
← Back to Boiler Help & Advice The Baxi A.00.34 code means “Outdoor temperature sensor expected but not detected.” The boiler’s configured control system expects information from an outdoor
Baxi A.02.06 code: low heating-system pressure
← Back to Boiler Help & Advice The Baxi A.02.06 code means low system pressure in the heating circuit. The sealed heating system does not have the pressure the boiler expects for normal oper
Baxi A.02.18 code: OBD error
← Back to Boiler Help & Advice The Baxi A.02.18 code means “OBD error”. That is the complete public wording in Baxi’s current error-code table for the relevant Combi 2 and System 2 boilers.
Baxi A.02.36 code: functional device disconnected
← Back to Boiler Help & Advice The Baxi A.02.36 code means “Functional device disconnected.” The boiler expects a functional device within its configured control system but is no longer dete
Baxi A.02.37 code: passive functional device disconnected
← Back to Boiler Help & Advice The Baxi A.02.37 code means “Passive functional device disconnected.” The boiler’s configured control system expects a passive functional device but is not det
Baxi A.02.45 code: connection error
← Back to Boiler Help & Advice The Baxi A.02.45 code means “Connection error.” That is the complete wording in Baxi’s current error-code information. It indicates that an expected technical
Baxi A.02.46 code: device-priority error
← Back to Boiler Help & Advice The Baxi A.02.46 code means “Device priority error.” It is a technical control-system message. The code indicates that the boiler has detected a problem with h
Baxi A.02.48 code: unit-function configuration error
← Back to Boiler Help & Advice The Baxi A.02.48 code means “Unit function configuration error.” This is the wording in Baxi’s current error-code information. It points to a technical configu
Baxi A.02.49 code: failed node initialisation
← Back to Boiler Help & Advice The Baxi A.02.49 code means “Failed node initialisation.” It is a technical controls message. In plain English, part of the boiler’s control system has not com
Baxi A.02.54 code: OpenTherm bus power-supply error
← Back to Boiler Help & Advice If your Baxi boiler shows A.02.54, Baxi’s official description is: “OpenTherm bus power supply error.” The boiler has detected a problem with the power supply
Baxi A.02.55 code: incorrect or missing serial number
← Back to Boiler Help & Advice The Baxi A.02.55 code means “Incorrect or missing serial number.” It is a technical identification-data message used by the boiler’s controls. It does not tell
Baxi A.02.76 code: settings customisation memory full
← Back to Boiler Help & Advice The Baxi A.02.76 code means “Internal memory reserved for full customisation of settings. No further changes can be made.” The boiler has reached the limit of
Baxi boiler display temperature rises but radiators stay cold
← Back to Boiler Help & Advice Baxi boiler display temperature rises but radiators stay cold A rising number on a Baxi display usually means the boiler water is getting hotter. It does not p
Baxi boiler fires and then stops after a minute
← Back to Boiler Help & Advice A Baxi boiler that fires for about a minute and then stops is not automatically faulty. Modern boilers turn the burner down, pause between demands and stop whe
Baxi boiler flame keeps going out
← Back to Boiler Help & Advice Baxi boiler flame keeps going out If a Baxi boiler lights and then loses its flame, its controls may retry or shut the appliance down. A single interruption ca
Baxi boiler gurgles when hot water runs
← Back to Boiler Help & Advice Baxi boiler gurgles when hot water runs A gurgling sound that starts when you open a hot tap does not identify one faulty part. It may be water moving through
Baxi boiler has heating but no hot water
← Back to Boiler Help & Advice If a Baxi boiler heats the radiators but produces no hot water, first identify whether it is a combi boiler or a boiler connected to a hot-water cylinder. On a
Baxi boiler heats the radiators when a hot tap is used
← Back to Boiler Help & Advice If radiators become noticeably hot whenever a hot tap is opened, a Baxi combi boiler may not be directing all of its heat to domestic hot water as intended. Ba
Baxi boiler hot water goes cold when a second tap opens
← Back to Boiler Help & Advice Baxi boiler hot water goes cold when a second tap opens If a Baxi combi boiler supplies a good hot shower or tap on its own but the water cools when a second o
Baxi boiler hot water temperature keeps changing
← Back to Boiler Help & Advice If a Baxi combi boiler’s hot water keeps changing from hot to cool, first work out whether the problem affects one shower or tap, or every hot outlet. That sim
Baxi boiler hot water too hot even on a low setting
← Back to Boiler Help & Advice Baxi boiler hot water too hot even on a low setting If water from a Baxi combi is still uncomfortably hot after the domestic-hot-water setting has been lowered
Baxi boiler hot water works but radiators stay cold
← Back to Boiler Help & Advice If a Baxi boiler still provides hot water but the radiators stay cold, the appliance has not necessarily failed completely. On a combi boiler, hot-water demand
Baxi boiler makes a loud bang when starting
← Back to Boiler Help & Advice Baxi boiler makes a loud bang when starting A loud bang as a Baxi boiler starts is not a noise to investigate by repeatedly firing the appliance. It may come f
Baxi boiler making a gurgling noise
← Back to Boiler Help & Advice A gurgling Baxi boiler does not point to one automatic diagnosis. In freezing weather, Baxi says gurgling can accompany a frozen external condensate pipe and b
Baxi boiler not firing and showing no fault code
← Back to Boiler Help & Advice A Baxi boiler that is not firing but shows no fault code is often waiting rather than locked out. The thermostat may not be asking for heat, the timer may be o
Baxi boiler pressure rises when hot water runs
← Back to Boiler Help & Advice A small rise on a Baxi boiler’s pressure gauge while a combi is making hot water can be normal. The boiler heats water in its sealed primary circuit to transfe
Baxi boiler pressure rises when the heating is on
← Back to Boiler Help & Advice Baxi boiler pressure rises when the heating is on A small rise in boiler pressure as the radiators warm up is normal. Water expands as it heats, and a sealed c
Baxi boiler radiators hot but no hot water
← Back to Boiler Help & Advice Baxi boiler radiators hot but no hot water If the radiators heat normally but taps stay cold, the boiler can produce heat but the hot-water side is not complet
Baxi boiler starts then stops after a few seconds
← Back to Boiler Help & Advice Baxi boiler starts then stops after a few seconds A Baxi boiler that fires briefly and stops may have completed a very small demand, or it may be losing the fl
Baxi Combi & System 2 E.01.04 fault code: flame loss detected five times in 24 hours
← Back to Boiler Help & Advice The Baxi E.01.04 fault code means “Flame loss detected five times in 24 hours.” Baxi lists that exact wording for its current Combi & System 2 boiler group. Th
Baxi Combi & System 2 E.01.17 fault code: no water circulation
← Back to Boiler Help & Advice If your Baxi Combi 2 or System 2 is showing E.01.17, Baxi defines the code as “No water circulation (permanent)”. In plain English, the boiler has detected tha
Baxi E.00.04 fault code: return temperature sensor disconnected
← Back to Boiler Help & Advice The Baxi E.00.04 fault code means “Return temperature sensor disconnected.” The boiler is not receiving the expected connection from the sensor used to monitor
Baxi E.00.05 fault code: return temperature sensor short-circuited
← Back to Boiler Help & Advice The Baxi E.00.05 fault code means “Return temperature sensor short circuited.” The boiler controls are receiving an electrical reading that matches Baxi’s shor
Baxi E.00.16 fault code: hot-water tank temperature sensor not connected
← Back to Boiler Help & Advice The Baxi E.00.16 fault code means “DHW tank temperature sensor not connected.” DHW means domestic hot water. On a system configured to monitor a hot-water tank
Baxi E.00.17 fault code: hot-water tank sensor short-circuited
← Back to Boiler Help & Advice The Baxi E.00.17 fault code means “DHW tank temperature sensor short-circuited.” DHW means domestic hot water. In plain English, the boiler control has detecte
Baxi E.00.20 fault code: flue gas temperature sensor not connected or below range
← Back to Boiler Help & Advice The Baxi E.00.20 fault code means the flue gas temperature sensor is not connected or has measured a temperature below its range. Those are the two possibiliti
Baxi E.00.21 fault code: flue gas temperature sensor short-circuited or above range
← Back to Boiler Help & Advice The Baxi E.00.21 fault code means the flue gas temperature sensor has short-circuited or measured a temperature above the range. Those are the two possibilitie
Baxi E.01.04 fault code explained
← Back to Boiler Help & Advice Baxi fault code E.01.04 means flame loss was detected five times within 24 hours. Baxi lists this exact meaning for applicable Combi 2 and System 2 boilers. Th
Baxi E.01.12 fault code: return temperature higher than flow temperature
← Back to Boiler Help & Advice Baxi fault code E.01.12 means the temperature measured by the return sensor is greater than the flow temperature. Baxi lists this exact description for applica
Baxi E.01.17 fault code: no water circulation (permanent)
← Back to Boiler Help & Advice Baxi fault code E.01.17 means no water circulation (permanent). Baxi lists this wording for applicable Combi 2 and System 2 boilers. It means the boiler has id
Baxi E.01.20 fault code: maximum flue-gas temperature reached
← Back to Boiler Help & Advice Baxi fault code E.01.20 means the maximum flue-gas temperature has been reached. Baxi lists this exact description for applicable Combi 2 and System 2 boilers.
Baxi E.02.13 fault code: total boiler stoppage with frost protection inactive
← Back to Boiler Help & Advice Baxi fault code E.02.13 means total stoppage of the boiler, with the antifreeze function not active. Baxi lists this wording for applicable Combi 2 and System
Baxi E.02.17 fault code: permanent communication failure between gas valve and PCB
← Back to Boiler Help & Advice Baxi fault code E.02.17 means a permanent communication failure between the gas valve and the boiler PCB. Baxi lists this exact meaning for applicable Combi 2
Baxi E.02.35 fault code: critical safety device disconnected
← Back to Boiler Help & Advice Baxi fault code E.02.35 means critical safety device disconnected. Baxi lists this wording for applicable Combi 2 and System 2 boilers. The boiler’s controls a
Baxi E.02.39 fault code explained
← Back to Boiler Help & Advice Baxi fault code E.02.39 means the minimum heating-system pressure was not reached after six minutes of automatic filling. That is the wording in Baxi’s current
Baxi E.02.47 fault code: external device connection unsuccessful
← Back to Boiler Help & Advice If your Baxi boiler shows E.02.47, Baxi’s official description is: “Connection to external device unsuccessful.” The boiler has been unable to establish or mai
Baxi E.04.01 fault code: flow temperature sensor short-circuited
← Back to Boiler Help & Advice Baxi fault code E.04.01 means the flow-temperature sensor is short-circuited. Baxi lists this exact meaning for applicable Combi 2 and System 2 boilers. The se
Baxi E.04.02 fault code: flow temperature sensor disconnected
← Back to Boiler Help & Advice Baxi fault code E.04.02 means the flow-temperature sensor is disconnected. Baxi lists this exact meaning for applicable Combi 2 and System 2 boilers. The flow-
Baxi E.04.03 fault code explained
← Back to Boiler Help & Advice Baxi fault code E.04.03 means either the maximum flow temperature has been exceeded or the flow-temperature sensor is short-circuited. Baxi lists both possibil
Baxi E.04.08 fault code explained
← Back to Boiler Help & Advice Baxi fault code E.04.08 means the maximum safe temperature value has been reached. Baxi lists this wording for applicable Combi 2 and System 2 boilers. The boi
Baxi E.04.10 fault code: burner failed to ignite after four attempts
← Back to Boiler Help & Advice Baxi fault code E.04.10 means the burner failed to ignite after four attempts. Baxi lists this exact description for applicable Combi 2 and System 2 boilers. T
Baxi E.04.12 fault code: ignition failure and flame monitoring
← Back to Boiler Help & Advice Baxi fault code E.04.12 means ignition failure – flame monitoring. Baxi uses this wording for applicable Combi 2 and System 2 boilers. In plain English, the bo
Baxi E.04.13 fault code: fan impeller blocked or maximum speed exceeded
← Back to Boiler Help & Advice Baxi fault code E.04.13 means the fan impeller is blocked or the maximum rpm has been exceeded. Baxi lists this wording for applicable Combi 2 and System 2 boi
Baxi E.04.17 fault code: gas valve control circuit fault
← Back to Boiler Help & Advice Baxi fault code E.04.17 means a fault in the gas valve control circuit. Baxi lists this wording for applicable Combi 2 and System 2 boilers. The boiler has det
Baxi E.04.18 fault code: low flow temperature or sensor not connected
← Back to Boiler Help & Advice Baxi fault code E.04.18 means the flow temperature is below the minimum temperature or the flow-temperature sensor is not connected. Baxi lists these two possi
Baxi E.04.23 fault code: internal communication stoppage
← Back to Boiler Help & Advice Baxi fault code E.04.23 means communication internal stoppage. Baxi lists this wording for applicable Combi 2 and System 2 boilers. The boiler’s controls rely
Baxi E.04.254 fault code: gas valve control circuit fault
← Back to Boiler Help & Advice Baxi fault code E.04.254 means a fault in the gas valve control circuit. Baxi lists this exact description for applicable Combi 2 and System 2 boilers. The app
Baxi E.04.29 fault code: internal communication stoppage
← Back to Boiler Help & Advice Baxi fault code E.04.29 means communication internal stoppage. Baxi gives this description for applicable Combi 2 and System 2 boilers. The boiler’s electronic
Baxi E.04.54 fault code: gas valve control circuit fault
← Back to Boiler Help & Advice Baxi fault code E.04.54 means a fault in the gas valve control circuit. Baxi lists this wording for applicable Combi 2 and System 2 boilers. The boiler has det
Baxi E09 fault code explained
← Back to Boiler Help & Advice If your Baxi boiler is showing E09, Baxi’s current error-code reference describes it as a gas valve connection fault on the covered models. This does not mean
Baxi E10 fault code explained
← Back to Boiler Help & Advice If your Baxi boiler is displaying E10, Baxi’s current error-code reference describes it as an external probe fault on the covered models. An external probe is
Baxi E103 fault code explained
← Back to Boiler Help & Advice Baxi E103 means the Safety Assist battery is exhausted. That is the exact description in Baxi’s current public error-code table. It does not mean the household
Baxi E104 fault code explained
← Back to Boiler Help & Advice Baxi E104 means the boiler has detected a faulty Safety Assist printed circuit board (PCB). That is Baxi’s current public error-code description. A PCB is an e
Baxi E107 fault code explained
← Back to Boiler Help & Advice Baxi E107 fault code explained If your Baxi boiler is showing E107, the manufacturer describes the fault as “PCBs not synchronised”. In plain English, the boil
Baxi E109 fault code explained
← Back to Boiler Help & Advice Baxi E109 fault code explained If your Baxi boiler is showing E109, the manufacturer describes it as a “precirculation alarm”. The boiler has detected a proble
Baxi E110 fault code explained: what it can mean
← Back to Boiler Help & Advice A plain E110 on the Baxi boiler families listed in the manufacturer’s current UK fault table is a high-temperature safety fault. Baxi describes two possible me
Baxi E118 fault code explained
← Back to Boiler Help & Advice Baxi E118 fault code explained Baxi identifies E118 as low heating-system water pressure: below 0.5 bar. The boiler may stop to protect itself because a sealed
Baxi E119 fault code explained
← Back to Boiler Help & Advice On several older Baxi, Potterton and Main boilers that share the same control-code family, E119 means the primary heating-system water pressure has fallen too
Baxi E12 fault code explained
← Back to Boiler Help & Advice If your Baxi boiler is showing E12, Baxi’s current error-code reference describes it as a differential water-flow switch fault, with the switch still open on t
Baxi E125 fault code explained
← Back to Boiler Help & Advice Baxi E125 fault code explained On the Baxi boiler ranges covered by the manufacturer’s current error-code table, E125 means a water-circulation fault. The boil
Baxi E13 fault code explained
← Back to Boiler Help & Advice If your Baxi boiler is showing E13, Baxi’s current error-code reference describes it as a differential water-flow switch fault, with the switch still closed on
Baxi E130 fault code explained
← Back to Boiler Help & Advice Baxi E130 fault code explained Baxi describes E130 as “flue thermostat sensor tripped (lockout)”. The boiler has stopped because a safety-related temperature c
Baxi E133 fault code explained
← Back to Boiler Help & Advice A Baxi boiler showing E133 has locked out because the gas supply was interrupted, ignition failed or the flame was not detected. Baxi also says a blocked or fr
Baxi E133 fault code explained: safe checks and next steps
← Back to Boiler Help & Advice A Baxi E133 fault means the boiler has locked out because it has not established safe operation. Baxi’s current error-code information describes E133 as a gas-
Baxi E135 fault code explained
← Back to Boiler Help & Advice The Baxi E135 fault code means internal error. That is the exact description in Baxi’s current error-code table for the affected combi and system boiler group.
Baxi E15 fault code explained
← Back to Boiler Help & Advice If your Baxi boiler is displaying E15, Baxi’s current error-code reference describes it as a gas valve command fault on the covered models. The meaning is mode
Baxi E154 fault code explained
← Back to Boiler Help & Advice Baxi E154 fault code explained Baxi describes the E154 fault as a “plausibility test (flow/return)” fault. In plain English, the boiler has compared the temper
Baxi E160 fault code explained
← Back to Boiler Help & Advice Baxi E160 fault code explained On the Baxi model group covered by the manufacturer’s current error-code table, E160 means a fan fault. The boiler may stop and
Baxi E20 fault code explained
← Back to Boiler Help & Advice Baxi E20 fault code: what it means and what to do Baxi fault code E20 means the boiler has detected a problem with the central-heating NTC temperature sensor.
Baxi E20 fault code explained: what to check safely
← Back to Boiler Help & Advice On the Baxi models that use the plain E20 code, Baxi defines it as a central-heating NTC temperature-sensor fault: the sensor circuit is open or short-circuite
Baxi E25 fault code explained
← Back to Boiler Help & Advice A Baxi E25 code is model-specific, so confirm the complete boiler model before accepting an online meaning. Baxi’s current UK error-code page does not list E25
Baxi E25 fault code explained: homeowner guide
← Back to Boiler Help & Advice If a UK Baxi boiler is showing E25, do not assume the first meaning found on a fault-code website applies to it. Baxi’s current UK “common error codes” page do
Baxi E270 fault code explained
← Back to Boiler Help & Advice Baxi E270 fault code: what it means and what to do Baxi fault code E270 is described by the manufacturer as a dry-fire fault. The boiler has detected a conditi
Baxi E28 fault code explained
← Back to Boiler Help & Advice Baxi E28 fault code explained A Baxi E28 code does not have one universal meaning across every Baxi boiler. Baxi’s current professional error-code table lists
Baxi E28 fault code explained: safe next steps
← Back to Boiler Help & Advice A plain E28 code on the Baxi boiler families listed in the manufacturer’s current UK table means a flue NTC temperature-sensor circuit fault: short circuit or
Baxi E317 / 162 fault code explained
← Back to Boiler Help & Advice If your Baxi boiler is showing E317 or 162, the manufacturer’s current error-code table describes it as “wrong power supply electrical frequency (Hz)”. In plai
Baxi E321 fault code explained
← Back to Boiler Help & Advice Baxi E321 fault code explained Baxi lists E321, also shown as code 163 on some controls, as a domestic-hot-water NTC sensor fault. The sensor circuit may be op
Baxi E384 / 164 fault code explained
← Back to Boiler Help & Advice If your Baxi boiler is showing E384 or 164, the current Baxi error-code guide describes it as false flame (parasitic flame). In plain English, the boiler’s con
Baxi E384 fault code explained
← Back to Boiler Help & Advice The Baxi E384 fault code means false flame (parasitic flame). Some compatible controls may show the equivalent code 164. In plain English, the boiler’s control
Baxi E385 / 165 fault code explained
← Back to Boiler Help & Advice If your Baxi boiler is showing E385 or 165, Baxi’s current error-code table describes it as under voltage. The boiler has detected that the electrical supply r
Baxi E385 fault code explained
← Back to Boiler Help & Advice Baxi E385 fault code explained Baxi identifies E385, also shown as code 165 on some controls, as an under-voltage fault. The boiler has detected that its elect
Baxi E40 fault code explained
← Back to Boiler Help & Advice Baxi E40 fault code: what it means and what to do Baxi fault code E40 means the boiler has detected an electrical fault with the return central-heating NTC tem
Baxi E430 / 166 fault code explained
← Back to Boiler Help & Advice If your Baxi boiler is showing E430 or 166, Baxi’s current error-code table describes it as a water pressure temporary fault. The boiler has detected a pressur
Baxi E430 fault code explained
← Back to Boiler Help & Advice The Baxi E430 fault code — also shown as code 166 on compatible controls — means a temporary water-pressure fault. If E430/166 appears with the crossed-flame s
Baxi E50 fault code explained
← Back to Boiler Help & Advice Baxi E50 indicates a domestic-hot-water NTC sensor fault on the tank-boiler applications covered by Baxi’s current error-code table. The manufacturer describes
Baxi E83 fault code explained
← Back to Boiler Help & Advice Baxi E83 is a communication fault. Baxi’s current error-code table groups E83 with E84, E85, E86 and E87 under “no communication”. The public code description
Baxi H.00.42 code: pressure sensor open or faulty
← Back to Boiler Help & Advice Baxi code H.00.42 means pressure sensor open or faulty. Baxi lists this wording for applicable Combi 2 and System 2 boilers. The message concerns the boiler’s
Baxi H.00.81 code: room unit disconnected
← Back to Boiler Help & Advice Baxi code H.00.81 means room unit disconnected. Baxi lists this wording for applicable Combi 2 and System 2 boilers. A room unit is a control used to communica
Baxi H.01.00 code: temporary gas valve and PCB communication failure
← Back to Boiler Help & Advice The Baxi H.01.00 code means a temporary communication failure between the gas valve and boiler PCB. It describes an interrupted control signal inside the appli
Baxi H.01.00 fault code explained
← Back to Boiler Help & Advice Baxi code H.01.00 means a temporary communication failure between the gas valve and boiler PCB. Baxi lists this wording for applicable Combi 2 and System 2 boi
Baxi H.01.05 fault code explained
← Back to Boiler Help & Advice Baxi code H.01.05 means the maximum temperature difference between flow and return has been reached. Baxi lists this wording for applicable Combi 2 and System
Baxi H.01.08 code: flow temperature rising too quickly
← Back to Boiler Help & Advice If your Baxi boiler shows H.01.08, the official meaning is: “Flow temperature increase in heating mode too quick. Temporary stoppage of 10 minutes.” In plain E
Baxi H.01.14 code: maximum flow or return temperature reached
← Back to Boiler Help & Advice Baxi code H.01.14 means the maximum flow or return temperature value has been reached. Baxi lists this wording for applicable Combi 2 and System 2 boilers. The
Baxi H.01.18 code: no water circulation (temporary)
← Back to Boiler Help & Advice Baxi code H.01.18 means no water circulation (temporary). Baxi lists this wording for applicable Combi 2 and System 2 boilers. The controls have detected that
Baxi H.01.21 code: flow temperature rising too fast during hot water use
← Back to Boiler Help & Advice Baxi code H.01.21 means the flow temperature increased too quickly during domestic hot-water operation. Baxi lists this exact meaning for applicable Combi 2 an
Baxi H.02.00 code: boiler reset in progress
← Back to Boiler Help & Advice The Baxi H.02.00 code means “reset in progress”. It is a status message showing that the boiler is working through a reset sequence. It is not, on its own, the
Baxi H.02.02 code: waiting for configuration settings
← Back to Boiler Help & Advice If your Baxi boiler shows H.02.02, Baxi’s official description is: “Waiting for configuration settings to be entered (CN1, CN2).” The boiler’s control system i
Baxi H.02.03 code: configuration settings entered incorrectly
← Back to Boiler Help & Advice If your Baxi boiler shows H.02.03, Baxi’s official description is: “Configuration settings (CN1, CN2) not entered correctly.” The boiler has detected that tech
Baxi H.02.04 code: boiler PCB settings cannot be read
← Back to Boiler Help & Advice If your Baxi boiler shows H.02.04, Baxi’s official description is: “PCB settings cannot be read.” In plain English, the boiler’s control system is unable to re
Baxi H.02.05 code: setting memory incompatible with boiler PCB
← Back to Boiler Help & Advice If your Baxi boiler shows H.02.05, Baxi’s official description is: “Setting memory not compatible with the boiler PCB type.” The boiler’s control system has de
Baxi H.02.07 code: permanently low heating-system pressure
← Back to Boiler Help & Advice If your Baxi boiler shows H.02.07, Baxi’s official meaning is: “Low pressure in heating circuit (permanently).” The boiler has detected that pressure in the se
Baxi H.02.09 code: partial stoppage with frost protection active
← Back to Boiler Help & Advice If your Baxi boiler shows H.02.09, Baxi’s official description is: “Partial stoppage of the boiler (antifreeze function active).” The boiler has restricted par
Baxi H.02.10 code: total boiler stoppage with frost protection inactive
← Back to Boiler Help & Advice The Baxi H.02.10 code means “Total stoppage of the boiler (antifreeze function not active).” The boiler has stopped operating and its built-in antifreeze funct
Baxi H.03.00 code: no identification data for boiler safety device
← Back to Boiler Help & Advice If your Baxi boiler shows H.03.00, Baxi’s official description is: “No identification data for boiler safety device.” The boiler’s control system cannot access
Baxi H.03.02 code: temporary flame loss
← Back to Boiler Help & Advice The Baxi H.03.02 code means “Temporary flame loss.” The boiler control detected that a flame which had been established was no longer present for a time. “Temp
Baxi H.03.05 code: power-supply voltage too low
← Back to Boiler Help & Advice The Baxi H.03.05 code means “Power supply voltage too low.” The boiler control has detected that its electrical supply is below the level it expects for normal
Baxi H.03.05 fault code explained
← Back to Boiler Help & Advice Baxi code H.03.05 means the power-supply voltage is too low. Baxi lists it for the applicable Combi 2 and System 2 boiler ranges. It is an electrical-supply me
Baxi H.03.54 code: temporary flame loss caused by low supply voltage
← Back to Boiler Help & Advice The Baxi H.03.54 code means “Temporary flame loss. Shutdown due to the power supply voltage being too low.” In plain English, the boiler detected that the flam
Baxi H.03.54 fault code explained
← Back to Boiler Help & Advice Baxi code H.03.54 means temporary flame loss, with the boiler shutting down because the power-supply voltage is too low. That is the wording in Baxi’s current
Baxi Platinum Compact E09 fault code: gas valve connection fault
← Back to Boiler Help & Advice Baxi Platinum Compact E09 fault code: gas valve connection fault A Baxi Platinum Compact showing E09 is reporting a gas valve connection fault. That is the exa
Baxi Platinum Compact E103 fault code: Safety Assist battery exhausted
← Back to Boiler Help & Advice If a Baxi Platinum Compact Combi shows E103, Baxi’s current error-code table describes the fault as “Safety Assist battery is exhausted.” The message names the
Baxi Platinum Compact E107 fault code: boiler PCBs not synchronised
← Back to Boiler Help & Advice Baxi Platinum Compact E107 fault code: what “PCBs not synchronised” means E107 on a Baxi Platinum Compact Combi means the boiler’s printed circuit boards are n
Baxi Platinum Compact E109 fault code: precirculation alarm
← Back to Boiler Help & Advice Baxi Platinum Compact E109 fault code: precirculation alarm A Baxi Platinum Compact showing E109 has reported a precirculation alarm. Baxi uses that exact word
Baxi Platinum Compact E110 fault code: maximum temperature / safety thermostat
← Back to Boiler Help & Advice Baxi Platinum Compact E110 fault code: maximum temperature or safety thermostat E110 on a Baxi Platinum Compact Combi is a safety-related temperature fault. Ba
Baxi Platinum Compact E12 fault code: differential water flow switch open
← Back to Boiler Help & Advice Baxi Platinum Compact E12 fault code: differential water flow switch open A Baxi Platinum Compact displaying E12 is reporting a differential water-flow switch
Baxi Platinum Compact E125 fault code: water circulation fault
← Back to Boiler Help & Advice Baxi Platinum Compact E125 fault code: water circulation fault A Baxi Platinum Compact showing E125 has reported a water circulation fault. Baxi uses that word
Baxi Platinum Compact E128 fault code: frequent loss of flame
← Back to Boiler Help & Advice Baxi Platinum Compact E128 fault code: frequent loss of flame E128 on a Baxi Platinum Compact Combi means “Safety error for frequent loss of flame”. The boiler
Baxi Platinum Compact E129 fault code: flame loss during calibration
← Back to Boiler Help & Advice Baxi Platinum Compact E129 fault code: what it means and what to do If your Baxi Platinum Compact displays E129, the boiler has recorded repeated flame loss du
Baxi Platinum Compact E13 fault code: differential water flow switch closed
← Back to Boiler Help & Advice Baxi Platinum Compact E13 fault code: differential water flow switch closed A Baxi Platinum Compact showing E13 is reporting a differential water-flow switch f
Baxi Platinum Compact E130 fault code: flue thermostat sensor tripped
← Back to Boiler Help & Advice Baxi Platinum Compact E130 fault code: what it means and what to do If your Baxi Platinum Compact shows E130, the boiler has stopped because a flue thermostat
Baxi Platinum Compact E134 fault code: gas valve open without gas
← Back to Boiler Help & Advice Baxi Platinum Compact E134 fault code: meaning and safe next steps If your Baxi Platinum Compact displays E134, the boiler has stopped after a gas-and-ignition
Baxi Platinum Compact E135 fault code: internal error
← Back to Boiler Help & Advice Baxi Platinum Compact E135 fault code: safe homeowner guidance An E135 code on a Baxi Platinum Compact has a short official meaning: “Internal error.” That is
Baxi Platinum Compact E15 fault code: gas valve command fault
← Back to Boiler Help & Advice Baxi Platinum Compact E15 fault code: gas valve command fault A Baxi Platinum Compact showing E15 has reported a gas valve command fault. That is the manufactu
Baxi Platinum Compact E154 fault code: flow and return plausibility
← Back to Boiler Help & Advice Baxi Platinum Compact E154 fault code: flow and return plausibility explained If your Baxi Platinum Compact displays E154, the boiler has found that the temper
Baxi Platinum Compact E160 fault code: fan fault
← Back to Boiler Help & Advice Baxi Platinum Compact E160 fault code: fan fault explained If your Baxi Platinum Compact displays E160, Baxi’s current manufacturer table gives the official me
Baxi Platinum Compact E270 fault code: dry fire
← Back to Boiler Help & Advice Baxi Platinum Compact E270 fault code: what “dry fire” means E270 on a Baxi Platinum Compact means the boiler has recorded a dry fire fault. That is the manufa
Baxi Platinum Compact E28 fault code: flue NTC sensor fault
← Back to Boiler Help & Advice Baxi Platinum Compact E28 fault code: meaning and safe next steps An E28 code on a Baxi Platinum Compact means “flue NTC sensor fault — short circuit/open circ
Baxi Platinum Compact E317 / 162 fault code: wrong electrical frequency
← Back to Boiler Help & Advice Baxi Platinum Compact E317 / 162 fault code: wrong electrical frequency If your Baxi Platinum Compact displays E317 / 162, the manufacturer describes the fault
Baxi Platinum Compact E321 / 163 fault code: domestic hot-water NTC sensor fault
← Back to Boiler Help & Advice Baxi Platinum Compact E321 / 163 fault code: hot-water NTC sensor fault E321 / 163 on a Baxi Platinum Compact is listed as a domestic hot-water NTC sensor faul
Baxi Platinum Compact E384 / 164 fault code: false flame
← Back to Boiler Help & Advice Baxi Platinum Compact E384 / 164 fault code: false flame explained E384 / 164 on a Baxi Platinum Compact is listed as “False flame (parasitic flame)”. The boil
Baxi Platinum Compact E385 / 165 fault code: under voltage
← Back to Boiler Help & Advice Baxi Platinum Compact E385 / 165 fault code: under voltage If your Baxi Platinum Compact shows E385 / 165, the manufacturer lists the fault as “Under voltage”.
Baxi Platinum Compact E40 fault code: return heating NTC sensor fault
← Back to Boiler Help & Advice Baxi Platinum Compact E40 fault code: meaning and safe next steps On a Baxi Platinum Compact Combi, E40 means “return central heating NTC sensor fault — short
Baxi Platinum Compact E430 / 166 fault code: temporary water-pressure fault
← Back to Boiler Help & Advice Baxi Platinum Compact E430 / 166 fault code: temporary water-pressure fault If your Baxi Platinum Compact displays plain E430 / 166, the manufacturer describes
Baxi Platinum Compact E430 / 166 with crossed-flame symbol: water-pressure test failed
← Back to Boiler Help & Advice Baxi Platinum Compact E430 / 166 with crossed-flame symbol: water-pressure test failed If your Baxi Platinum Compact shows E430 or 166 together with a crossed-
Baxi Platinum Compact E83 fault code: communication error
← Back to Boiler Help & Advice Baxi Platinum Compact E83 fault code: what “no communication” means A Baxi Platinum Compact displaying E83 has reported a “no communication” fault. Baxi’s curr
Boiler condensate pipe leaking indoors
← Back to Boiler Help & Advice A condensing boiler normally produces water and sends it through a plastic condensate pipe to a household drain. That water should remain inside the pipework.
Boiler display is blank but power is on
← Back to Boiler Help & Advice A completely blank boiler display usually points to a loss of electrical power or a fault inside the appliance—not a thermostat setting or an ordinary boiler e
Boiler fires up but there is no flame: what now?
← Back to Boiler Help & Advice A boiler can start its fan or pump, make an ignition sound and light up its display without ever establishing a burner flame. If the flame is not safely proved
Boiler heats the radiators but the room thermostat still reads cold
← Back to Boiler Help & Advice Boiler heats the radiators but the room thermostat still reads cold A room thermostat measures the air immediately around it, not the temperature of the radiat
Boiler is running but radiators are not heating: what now?
← Back to Boiler Help & Advice If the boiler sounds as though it is running but the radiators remain cold, first establish what “running” means. A lit display or humming pump does not necess
Boiler keeps clicking repeatedly before it starts
← Back to Boiler Help & Advice One or two brief clicks as a gas boiler begins its ignition sequence can be normal, but repeated clicking before every start deserves attention. It may be the
Boiler loses pressure after radiator bleeding
← Back to Boiler Help & Advice A small pressure drop after bleeding a radiator is usually expected. Bleeding releases trapped air and often a little water from a sealed heating circuit, so t
Boiler losing pressure with no visible leak
← Back to Boiler Help & Advice Boiler losing pressure with no visible leak A sealed heating system should not need frequent topping up. If the gauge keeps falling but there is no puddle, wat
Boiler makes a humming or vibrating noise
← Back to Boiler Help & Advice A quiet hum for a few seconds can be part of normal boiler operation. A new, loud or continuous vibration is different: it may come from the boiler, a nearby p
Boiler makes a noise after bleeding radiators
← Back to Boiler Help & Advice A new noise after bleeding radiators is commonly linked to changed system pressure or air still moving through the pipework. A brief rush or gurgle when heatin
Boiler not firing up: safe checks before calling an engineer
← Back to Boiler Help & Advice If your boiler is not firing up, the cause may be as simple as a changed timer, low system pressure or an interrupted supply. It may also be an ignition, contr
Boiler pressure display and analogue gauge do not match
← Back to Boiler Help & Advice Boiler pressure display and analogue gauge do not match A small difference between a boiler’s digital pressure reading and its round analogue gauge is not auto
Boiler pressure drops when heating is off
← Back to Boiler Help & Advice Boiler pressure normally falls a little as the heating switches off and the water cools. That is the reverse of the small rise you see when the system warms. T
Boiler pressure gauge is stuck
← Back to Boiler Help & Advice Boiler pressure gauge is stuck A boiler pressure gauge that never moves can give false reassurance or make safe topping up impossible. The needle may be jammed
Boiler pressure is normal but the radiators stay cold
← Back to Boiler Help & Advice Boiler pressure is normal but the radiators stay cold A normal pressure reading means a sealed heating circuit is not obviously short of water at that moment.
Boiler pressure relief pipe dripping outside: what does it mean?
← Back to Boiler Help & Advice Water dripping from a boiler pressure-relief pipe outside usually means the sealed heating system has discharged water or the safety valve is no longer sealing
Boiler pressure rises to 3 bar when heating is on
← Back to Boiler Help & Advice A boiler pressure gauge that climbs towards 3 bar whenever the heating comes on is not behaving normally. A small rise as the system warms is expected, but a l
Boiler repair: what homeowners should expect
← Back to Boiler Help & Advice A good boiler repair starts with diagnosis, not guesswork. The engineer needs to understand the symptoms, inspect and test the appliance safely, identify the c
Boiler service or gas safety check: what is the difference?
← Back to Boiler Help & Advice A boiler service and a landlord gas-safety check are not the same job. They overlap because both involve safe operation, but they have different purposes, scop
Boiler smells unusual: which smells need urgent action?
← Back to Boiler Help & Advice An unusual smell near a boiler should never be diagnosed by scent alone. A gas-like smell, burning or melting-plastic smell, smoke, scorching, a carbon-monoxid
Boiler works after reset but fails again the next day
← Back to Boiler Help & Advice Boiler works after reset but fails again the next day If a boiler works after a reset but fails again hours or a day later, the reset has cleared the lockout,
Boiler works downstairs but upstairs radiators stay cold
← Back to Boiler Help & Advice Boiler works downstairs but upstairs radiators stay cold If the downstairs radiators warm up but the upstairs ones remain cold, the boiler is producing some he
Boiler works upstairs but downstairs radiators stay cold
← Back to Boiler Help & Advice Boiler works upstairs but downstairs radiators stay cold Hot upstairs radiators show that the boiler can produce heat, but they do not prove every heating zone
Boilers and carbon monoxide: warning signs and safe action
← Back to Boiler Help & Advice Carbon monoxide can be produced when a fuel-burning appliance is faulty, poorly maintained or does not receive enough air for correct combustion. A gas boiler
Can a boiler fault affect only one hot tap?
← Back to Boiler Help & Advice Can a boiler fault affect only one hot tap? It is possible, but if every other hot tap works normally, the affected tap, its mixer, a flexible connector or the
Can a boiler pump run for longer after a service?
← Back to Boiler Help & Advice Can a boiler pump run for longer after a service? Yes, a circulation pump can keep running after the burner has stopped. This is usually called pump overrun: i
Can a boiler service change how quickly radiators warm up?
← Back to Boiler Help & Advice Can a boiler service change how quickly radiators warm up? Yes, although a routine boiler service is not intended to transform the whole heating system. Radiat
Can a cold hallway make a carbon-monoxide alarm show a battery warning?
← Back to Boiler Help & Advice Can a cold hallway make a carbon-monoxide alarm show a battery warning? It can contribute, because battery voltage can fall in cold conditions and every alarm
Can a cooker hood affect a boiler in another room?
← Back to Boiler Help & Advice Can a cooker hood affect a boiler in another room? Yes, it can—because rooms in a home are connected by doorways, gaps and ventilation routes. A cooker hood th
Can a cooker hood make a wireless thermostat lose connection?
← Back to Boiler Help & Advice Can a cooker hood make a wireless thermostat lose connection? It is possible for a cooker hood to coincide with a wireless thermostat problem, but the timing d
Can a deep windowsill trap heat above a radiator?
← Back to Boiler Help & Advice Can a deep windowsill trap heat above a radiator? Yes. A deep windowsill close above a radiator can interrupt the warm air rising from it. The sill may redirec
Can a dripping hot tap make a cylinder reheat more often?
← Back to Boiler Help & Advice Can a dripping hot tap make a cylinder reheat more often? Yes, it can. A hot tap that never fully closes may slowly remove water from a hot-water cylinder. Col
Can a dripping pumped tap make a shower pump cycle briefly?
← Back to Boiler Help & Advice Can a dripping pumped tap make a shower pump cycle briefly? Yes. On a universal or negative-head pump, a dripping tap or another small leak on the pumped side
Can a games console make a nearby thermostat read too warm?
← Back to Boiler Help & Advice Can a games console make a nearby thermostat read too warm? Yes. A games console uses electrical energy and removes heat from its components with cooling airfl
Can a heated airer beside a radiator change a TRV reading?
← Back to Boiler Help & Advice Can a heated airer beside a radiator change a TRV reading? Yes. A thermostatic radiator valve responds to the air around its sensor, not to an average temperat
Can a heated clothes airer affect a nearby thermostat?
← Back to Boiler Help & Advice Can a heated clothes airer affect a nearby thermostat? Yes. A heated clothes airer converts electrical energy into heat. If it is close to a room thermostat, o
Can a landlord arrange a boiler repair when the tenant is away?
← Back to Boiler Help & Advice Can a landlord arrange a boiler repair when the tenant is away? Yes. A boiler repair can usually go ahead while a tenant is away if the tenant has agreed how a
Can a large television affect the thermostat reading nearby?
← Back to Boiler Help & Advice Can a large television affect the thermostat reading nearby? Yes. A television converts most of the electricity it uses into heat, and warm air rises from its
Can a letterbox draught make the hall thermostat call for heat?
← Back to Boiler Help & Advice Can a letterbox draught make the hall thermostat call for heat? Yes. If a room thermostat is close to the front door, cold air entering through the letterbox o
Can a loft conversion change how upstairs radiators heat?
← Back to Boiler Help & Advice Can a loft conversion change how upstairs radiators heat? Yes. A loft conversion changes the heated shape of the home. A new room, extra radiator, longer pipe
Can a log burner make the thermostat switch the heating off too soon?
← Back to Boiler Help & Advice Can a log burner make the thermostat switch the heating off too soon? Yes. If a log burner warms the room containing the main thermostat, the thermostat can re
Can a long pipe run make upstairs hot water arrive slowly?
← Back to Boiler Help & Advice Can a long pipe run make upstairs hot water arrive slowly? Yes. The longer the route from the boiler or cylinder to an upstairs outlet, the more cooled water m
Can a mixer tap make the boiler fire unexpectedly?
← Back to Boiler Help & Advice Can a mixer tap make the boiler fire unexpectedly? Yes. On a combi boiler, moving a mixer tap towards the hot side can create a hot-water demand even before th
Can a new bath tap expose an existing hot-water flow problem?
← Back to Boiler Help & Advice Can a new bath tap expose an existing hot-water flow problem? Yes. A new bath tap can pass water differently from the old one, so an existing limit in the inco
Can a new kitchen extractor change a nearby room thermostat reading?
← Back to Boiler Help & Advice Can a new kitchen extractor change a nearby room thermostat reading? Yes, it can change the air moving past a nearby thermostat, although the extractor is not
Can a partially blocked tap aerator make hot water seem intermittent?
← Back to Boiler Help & Advice Can a partially blocked tap aerator make hot water seem intermittent? Yes. Limescale or debris in the small aerator at the end of a tap can reduce flow and dis
Can a partially closed shower valve make a combi boiler cycle?
← Back to Boiler Help & Advice Can a partially closed shower valve make a combi boiler cycle? Yes. A partly closed isolating valve, restricted mixer, blocked filter or clogged shower head ca
Can a partly closed stop tap affect a combi boiler?
← Back to Boiler Help & Advice Can a partly closed stop tap affect a combi boiler? Yes. A combi boiler heats mains water as it flows through the appliance. If the internal stop tap restricts
Can a portable dehumidifier affect a nearby room thermostat reading?
← Back to Boiler Help & Advice Can a portable dehumidifier affect a nearby room thermostat reading? Yes. A portable dehumidifier moves a steady stream of air and releases some heat while it
Can a power cut change my boiler timer or heating schedule?
← Back to Boiler Help & Advice Can a power cut change my boiler timer or heating schedule? Yes. Some heating controls remember their schedule through a power cut, while others lose the curre
Can a pressure-reducing valve change appliance-related water hammer?
← Back to Boiler Help & Advice Can a pressure-reducing valve change appliance-related water hammer? Yes. A correctly selected and commissioned pressure-reducing valve—often shortened to PRV—
Can a pressure-reducing valve change mixer shower temperature?
← Back to Boiler Help & Advice Can a pressure-reducing valve change mixer shower temperature? Yes. A pressure-reducing valve, or PRV, changes the pressure available downstream. If it affects
Can a pull-out kitchen tap drip after the handle is closed?
← Back to Boiler Help & Advice Can a pull-out kitchen tap drip after the handle is closed? Yes. A few drops can leave the spray head after shut-off because water remains in the spout, head a
Can a radiator shelf change how quickly a room warms?
← Back to Boiler Help & Advice Can a radiator shelf change how quickly a room warms? A shelf above a radiator can change where the rising warm air goes. With sensible clearance, it may encou
Can a sealed carbon-monoxide alarm battery be replaced?
← Back to Boiler Help & Advice Can a sealed carbon-monoxide alarm battery be replaced? Usually, no. In a sealed-battery carbon-monoxide alarm, the power cell is built into the unit and is no
Can a shared water main affect a combi shower at peak times?
← Back to Boiler Help & Advice Can a shared water main affect a combi shower at peak times? Yes. Several properties can share part of the pipe connecting them to the water main, especially i
Can a shower filter change how a combi boiler delivers hot water?
← Back to Boiler Help & Advice Can a shower filter change how a combi boiler delivers hot water? Yes. Any filter fitted in the shower’s water path can add resistance and reduce flow. A clean
Can a shower flow regulator be too restrictive for a combi?
← Back to Boiler Help & Advice Can a shower flow regulator be too restrictive for a combi? It can be, but the regulator should not be blamed from the litres-per-minute number alone. A combi
Can a shower temperature change when a toilet cistern fills slowly?
← Back to Boiler Help & Advice Can a shower temperature change when a toilet cistern fills slowly? Yes. A toilet cistern that takes a long time to refill can keep drawing cold water for long
Can a sunny room make a smart heating zone switch off early?
← Back to Boiler Help & Advice Can a sunny room make a smart heating zone switch off early? Yes. Winter sun can genuinely warm a room, and direct sunlight can also warm the thermostat or sma
Can a tap aerator make a combi boiler fail to detect hot-water demand?
← Back to Boiler Help & Advice Can a tap aerator make a combi boiler fail to detect hot-water demand? Yes. A tap aerator can deliberately limit flow, and scale or debris can restrict it furt
Can a thermostat display stay on with batteries too weak to transmit?
← Back to Boiler Help & Advice Can a thermostat display stay on with batteries too weak to transmit? Yes. A display can use very little power, while the radio transmitter needs a stronger bu
Can a thermostatic shower still change temperature when another tap opens?
← Back to Boiler Help & Advice Can a thermostatic shower still change temperature when another tap opens? Yes. A thermostatic mixer is designed to keep the shower temperature more stable as
Can a tumble dryer change how the nearby thermostat behaves?
← Back to Boiler Help & Advice Can a tumble dryer change how the nearby thermostat behaves? Yes. A working tumble dryer releases some heat into the room and moves air around its installation
Can a water softener change combi-boiler hot-water flow?
← Back to Boiler Help & Advice Can a water softener change combi-boiler hot-water flow? A water softener becomes part of the mains-water route through the home. A correctly selected and inst
Can a water-saving shower head make a combi boiler cycle?
← Back to Boiler Help & Advice Can a water-saving shower head make a combi boiler cycle? Yes, it can in some installations—but a water-saving head is not automatically faulty or unsuitable.
Can an air purifier affect a nearby room thermostat reading?
← Back to Boiler Help & Advice Can an air purifier affect a nearby room thermostat reading? Yes, an air purifier can sometimes influence the temperature shown by a nearby room thermostat, bu
Can an electric boiler preheat a home before peak tariff hours?
← Back to Boiler Help & Advice Can an electric boiler preheat a home before peak tariff hours? Yes, in some homes. A correctly controlled electric boiler can warm the building or a hot-water
Can an electric boiler share capacity with an electric shower?
← Back to Boiler Help & Advice Can an electric boiler share capacity with an electric shower? Sometimes—but not simply by connecting both and hoping the main fuse copes. An electric flow boi
Can an electric boiler work with existing radiators?
← Back to Boiler Help & Advice Can an electric boiler work with existing radiators? Yes—an electric flow boiler can often use an existing wet radiator circuit because it heats circulating wa
Can an electric drying pod make a room thermostat stop heating early?
← Back to Boiler Help & Advice Can an electric drying pod make a room thermostat stop heating early? Yes. A heated drying pod can create a local pocket or stream of warm air around a nearby
Can an immersion heater make the cylinder cupboard warmer than the boiler does?
← Back to Boiler Help & Advice Can an immersion heater make the cylinder cupboard warmer than the boiler does? It can, but it is not a universal rule. An immersion element heats stored water
Can an open stairwell make the hall thermostat run heating longer?
← Back to Boiler Help & Advice Can an open stairwell make the hall thermostat run heating longer? Yes. An open stairwell can create an easy route for warmer air to move out of the hall while
Can an upstairs tap aerator make a long hot-water wait seem worse?
← Back to Boiler Help & Advice Can an upstairs tap aerator make a long hot-water wait seem worse? Yes. An aerator or flow regulator at an upstairs tap can reduce the litres per minute leavin
Can changing mains water pressure affect a mixer shower temperature?
← Back to Boiler Help & Advice Can changing mains water pressure affect a mixer shower temperature? Yes. A mixer shower blends hot and cold water, so changes to the pressure or available flo
Can closing a kitchen door make the hallway thermostat run longer?
← Back to Boiler Help & Advice Can closing a kitchen door make the hallway thermostat run longer? Yes. A room thermostat measures the air around itself. If an open kitchen door normally lets
Can closing internal doors affect how the heating thermostat works?
← Back to Boiler Help & Advice Can closing internal doors affect how the heating thermostat works? Yes. Closing an internal door changes how warm air moves around the home. A single room the
Can closing internal doors change which rooms warm first?
← Back to Boiler Help & Advice Can closing internal doors change which rooms warm first? Yes. Closing an internal door reduces the movement of warm air and cooler draughts between rooms. A r
Can closing several radiator valves make another valve noisy?
← Back to Boiler Help & Advice Can closing several radiator valves make another valve noisy? Yes. When several thermostatic or manual radiator valves close, the heating water has fewer open
Can decorating or boxing in a boiler affect ventilation and access?
← Back to Boiler Help & Advice Can decorating or boxing in a boiler affect ventilation and access? Yes. A cupboard or decorative panel can look harmless but still block air openings, prevent
Can drying clothes indoors change how the heating thermostat behaves?
← Back to Boiler Help & Advice Can drying clothes indoors change how the heating thermostat behaves? Yes, although the effect is usually indirect. Wet laundry adds moisture to the air, and a
Can extractor fans make a draught around the boiler cupboard?
← Back to Boiler Help & Advice Can extractor fans make a draught around the boiler cupboard? Yes. An extractor fan removes air from a kitchen, bathroom or utility room. Replacement air then
Can fan post-purge time change after a boiler service?
← Back to Boiler Help & Advice Can fan post-purge time change after a boiler service? Yes, or it may only appear to. A boiler fan can continue after the burner stops to clear combustion prod
Can I get an electric combi boiler?
← Back to Boiler Help & Advice Can I get an electric combi boiler? Yes. Electric combination boilers are available, but the word “combi” can describe a different arrangement from the compact
Can missing pipe insulation make an airing cupboard much warmer?
← Back to Boiler Help & Advice Can missing pipe insulation make an airing cupboard much warmer? Yes. A bare hot-water or cylinder-primary pipe transfers more heat into the cupboard than the
Can moving a wireless thermostat closer make it reconnect?
← Back to Boiler Help & Advice Can moving a wireless thermostat closer make it reconnect? Yes—if the thermostat is a portable, battery model and distance or obstructions have weakened its li
Can new flooring change heating noises?
← Back to Boiler Help & Advice Can new flooring change heating noises? Yes. New flooring can change the way normal heating-pipe movement is heard, even when the boiler and radiators have not
Can pipe insulation make hot water reach a distant tap faster?
← Back to Boiler Help & Advice Can pipe insulation make hot water reach a distant tap faster? Pipe insulation can make a later hot-water draw feel faster because water left in the pipe stays
Central heating pump seems to run but radiators stay cold
← Back to Boiler Help & Advice A central-heating pump that can be heard or felt running does not prove that hot water is circulating through the radiators. The pump may be receiving power wh
Combi, system or regular boiler: what is the difference?
← Back to Boiler Help & Advice Combi, system and regular boilers can all heat radiators efficiently, but they provide hot water in different ways. That difference affects cupboard space, sho
Do closed internal doors affect how the thermostat controls heating?
← Back to Boiler Help & Advice Do closed internal doors affect how the thermostat controls heating? Yes. A room thermostat reacts to the temperature where it is fitted, not an average of the
Do Radiator Covers Really Block THAT Much Heat?
← Back to Boiler Help & Advice Radiator covers do not make heat disappear, but they can delay and redirect how it reaches the room. A restrictive cover can trap warm air, send more heat towa
Do smart thermostats work with older boilers?
← Back to Boiler Help & Advice A smart thermostat can work with many older boilers, but “older” is not a compatibility standard. The answer depends on the boiler’s control terminals, the hea
Does an electric boiler need a three-phase electricity supply?
← Back to Boiler Help & Advice Does an electric boiler need a three-phase electricity supply? Not every electric boiler needs three-phase electricity. Some domestic flow boilers are designed
Does lowering the heating flow temperature affect tap hot water?
← Back to Boiler Help & Advice Does lowering the heating flow temperature affect tap hot water? On most modern combi boilers, lowering the central-heating flow temperature should not lower t
Heating comes on in the middle of the night
← Back to Boiler Help & Advice Heating that comes on in the middle of the night is often responding to a control setting rather than switching itself on at random. A hidden schedule, frost-p
Heating works upstairs but not downstairs
← Back to Boiler Help & Advice If the radiators upstairs warm normally but the ground floor stays cold, the boiler is producing heat but that heat is not being distributed evenly. The cause
Hot water takes too long to reach the tap
← Back to Boiler Help & Advice Hot water rarely arrives the instant a tap opens. The cooled water already sitting between the boiler or cylinder and the outlet must leave first. But if the w
How can I tell if I need a Powerflush?
← Back to Boiler Help & Advice You may need a powerflush if tests show that sludge and debris are seriously restricting circulation around several parts of your wet central-heating system. C
How can I tell if the boiler filling loop was left open?
← Back to Boiler Help & Advice How can I tell if the boiler filling loop was left open? The clearest sign is boiler pressure that keeps rising while the heating is off and the system is cool
How do I program my Drayton thermostat?
← Back to Boiler Help & Advice To programme a Drayton thermostat correctly, start by finding the exact model number. Drayton Digistat, Digistat+ and Wiser controls use different buttons and
How do I program my EPH thermostat?
← Back to Boiler Help & Advice To programme an EPH thermostat, identify the exact model and select the correct schedule pattern before editing any times. Popular EPH CP4 and RFRP programmabl
How do I program my ESI thermostat?
← Back to Boiler Help & Advice To programme an ESi thermostat, first find the model number and then set its clock, schedule type and daily time-and-temperature events. On common Series 4 mod
How do I program my Hive Mini?
← Back to Boiler Help & Advice A Hive Thermostat Mini schedule is created and edited in the Hive app, not on the Mini itself. Open the app, tap Home, choose Heating and tap View Schedule. Se
How do I program my Honeywell thermostat?
← Back to Boiler Help & Advice To program a current Honeywell Home T3 or T4 thermostat, press Menu, select the heating schedule, choose the day and period, then set its time and temperature
How do I program my Salus thermostat?
← Back to Boiler Help & Advice To programme a Salus thermostat correctly, start with the model number. RT510, RT520 and iT500 controls use different buttons and menus, even though each can r
How do I programme my Hive thermostat?
← Back to Boiler Help & Advice You can programme a Hive thermostat in the Hive app, and many full-size dial models can also be programmed on the thermostat itself. In the current app, open H
How do I programme my Nest thermostat?
← Back to Boiler Help & Advice To programme a Google Nest thermostat, first identify the model and decide whether you want it to learn your routine or follow a fixed schedule. Nest Learning
How do I programme my Tado thermostat?
← Back to Boiler Help & Advice Programming a Tado thermostat is mainly about building a Smart Schedule for each room. Unlike a traditional programmer that switches the whole heating system o
How do I top up my Ideal Boiler pressure
← Back to Boiler Help & Advice If your Ideal boiler pressure has fallen, you may be able to top up the sealed heating system through its filling loop. Many Ideal Logic combis use a detachabl
How do I top up my Valliant boiler?
← Back to Boiler Help & Advice If your Vaillant boiler pressure is low, you may be able to restore it through the heating system’s filling device. The important first step is identifying the
How do I top up my Worcester boiler pressure?
← Back to Boiler Help & Advice If your Worcester Bosch boiler pressure has fallen below its normal range, you may be able to top it up using the filling arrangement fitted to your system. Wo
How do I top up the pressure on my Baxi/main boiler?
← Back to Boiler Help & Advice If the pressure on your Baxi, Main or Potterton boiler is below its normal range, you may be able to top it up using the filling link fitted to the heating sys
How do I use my Time:o:stat?
← Back to Boiler Help & Advice How do I use my Time:o:stat? A Time:o:stat is a countdown room thermostat commonly used in shared or bills-included properties. Instead of leaving the heating
How does a combi boiler work?
← Back to Boiler Help & Advice How does a combi boiler work? A combination—or combi—boiler provides central heating and hot water from one appliance. It heats water for your radiators in a c
How does a radiator work?
← Back to Boiler Help & Advice How does a radiator work? A central-heating radiator is a heat emitter. Hot water enters it through a valve, moves through its internal channels and leaves thr
How does underfloor heating work?
← Back to Boiler Help & Advice How does underfloor heating work? Underfloor heating turns a large area of floor into a gentle heat emitter. A wet system circulates warm water through pipes b
How much does a new boiler cost in the UK?
← Back to Boiler Help & Advice A straightforward gas-boiler replacement in Great Britain typically costs several thousand pounds once installation is included. Energy Saving Trust currently
How much electricity does an electric combi boiler use?
← Back to Boiler Help & Advice How much electricity does an electric combi boiler use? An electric combi boiler can draw several kilowatts while its heating elements are on, but its badge ra
How often should you service a boiler?
← Back to Boiler Help & Advice Most gas boilers should be serviced once a year by a Gas Safe registered engineer. That is the short answer. The slightly longer—and more useful—answer is that
How old is my boiler?
← Back to Boiler Help & Advice To find the age of a boiler, start with its installation paperwork and data plate. The serial number can help, but there is no single decoding rule that works
How to balance radiators
← Back to Boiler Help & Advice Balancing radiators means sharing the available hot-water flow so every room heats at a sensible rate. It is not the same as bleeding radiators, setting room t
How to bleed a radiator safely
← Back to Boiler Help & Advice If a radiator is warm at the bottom but cold at the top, trapped air may be stopping hot water from filling it properly. Bleeding releases that air through the
How to tell if a boiler fault is covered by warranty
← Back to Boiler Help & Advice You cannot tell whether a boiler fault is covered by warranty from the fault code alone. Coverage depends on the boiler’s registration, installation date, warr
How to top up your boiler pressure
← Back to Boiler Help & Advice If your boiler pressure is below its normal cold range, you may be able to restore it by letting a small amount of mains water into the sealed heating circuit.
How to top up your Viessmann Boiler
← Back to Boiler Help & Advice A Viessmann boiler with low pressure may stop providing reliable heating or hot water. If the exact operating instructions allow homeowner repressurising, you
I have a gas leak- what do I do?
← Back to Boiler Help & Advice If you have or suspect a gas leak, leave the affected area and call the National Gas Emergency Service on 0800 111 999 from outside or another safe place. Do n
I’ve booked a Fixed Price Boiler Repair- now what happens?
← Back to Boiler Help & Advice You have paid and your Incredaboil fixed-price boiler repair is booked. What happens next? The short answer is that your repair clock is already running, your
Ideal boiler display is blank
← Back to Boiler Help & Advice A completely blank Ideal boiler display usually means the controls are not receiving or showing electrical power. First distinguish a genuinely dark screen fro
Ideal boiler display keeps switching on and off
← Back to Boiler Help & Advice Ideal boiler display keeps switching on and off An Ideal boiler display can change or dim during normal operation, but a screen that repeatedly goes completely
Ideal boiler F2 fault code explained
← Back to Boiler Help & Advice On many current Ideal boilers, such as Logic Combi2, Logic System2 and Logic Heat2 literature, fault code F2 or F02 means flame loss. The boiler detected
Ideal boiler F3 fault code explained
← Back to Boiler Help & Advice On the Ideal ranges checked for this guide, fault code F3 or F03 means a fan fault. The boiler has not proved the fan operation it needs for a safe start or co
Ideal boiler fan fault: what should you do?
← Back to Boiler Help & Advice An Ideal boiler fan fault means the controls have detected that the combustion-air and flue-gas system is not behaving as expected. On the Ideal Logic Code Com
Ideal boiler fan runs but the burner does not light
← Back to Boiler Help & Advice Ideal boiler fan runs but the burner does not light An Ideal boiler normally runs its fan as part of the ignition sequence, and some models also use a fan over
Ideal boiler hot water is intermittent
← Back to Boiler Help & Advice Intermittent hot water from an Ideal boiler can mean different things: a combi may run hot, then cold, then hot again at the tap; a system or heat-only boiler
Ideal boiler hot water works but heating does not
← Back to Boiler Help & Advice Ideal boiler hot water works but heating does not If an Ideal combi supplies normal hot water but the radiators stay cold, the boiler can produce heat in at le
Ideal boiler hot water works but the heating does not
← Back to Boiler Help & Advice If an Ideal combi boiler produces hot water but the radiators do not heat, begin with heating mode and the external controls. Ideal’s user guides tells h
Ideal boiler keeps going into standby
← Back to Boiler Help & Advice Ideal boiler keeps going into standby Standby is usually a normal operating state, not a fault. On many Ideal boilers, a display of 0 or 00 means the boiler is
Ideal boiler keeps showing low pressure after topping up
← Back to Boiler Help & Advice If an Ideal boiler returns to low pressure after you top it up, the added water is going somewhere or the pressure reading is not reliable. A one-off drop afte
Ideal boiler L1 fault code explained
← Back to Boiler Help & Advice Ideal boiler L1 fault code explained On the Ideal Logic Code Combi ESP1 user guide, L1 means “Flow Temperature Overheat or No Water Flow”. The boiler has locke
Ideal boiler L2 fault code explained
← Back to Boiler Help & Advice On the Ideal Logic Code Combi ESP1, the manufacturer defines L2 as an ignition lockout. In plain English, the boiler attempted to establish a safe flame but di
Ideal boiler L5 fault code explained
← Back to Boiler Help & Advice Ideal boiler L5 fault code explained On several Ideal Logic-family boilers, L5 or F5 means a return thermistor fault. The return thermistor is a temperature se
Ideal boiler L9 fault code explained
← Back to Boiler Help & Advice On current Ideal Logic Combi2, Logic System2 and Logic Heat2 literature, fault code L9 or L09 is grouped with F9/F09 as an unconfigured PCB fault. Ideal’s user
Ideal boiler makes a humming noise but will not start
← Back to Boiler Help & Advice Ideal boiler makes a humming noise but will not start A hum tells you that something in or around the heating system may be energised, but it does not identify
Ideal boiler makes a vibrating noise
← Back to Boiler Help & Advice A vibrating Ideal boiler is not a diagnosis on its own. The timing matters: vibration can be linked to a fan, pump, water flow, a valve or pipework resonance,
Ideal boiler overheat fault explained
← Back to Boiler Help & Advice Ideal boiler overheat fault explained An Ideal boiler showing Overheat, L1 or L01 has stopped because its control system detected an excessive flow temperature
Ideal boiler pressure drops only after the heating cools
← Back to Boiler Help & Advice Ideal boiler pressure drops only after the heating cools A sealed heating system normally shows a slightly higher pressure when hot and a lower reading after i
Ideal boiler pressure rises overnight
← Back to Boiler Help & Advice Boiler pressure normally rises a little as heating water warms and expands, then falls as the system cools. If an Ideal boiler’s pressure climbs overnight whil
Ideal boiler pressure rises when hot water runs
← Back to Boiler Help & Advice Ideal boiler pressure rises when hot water runs A small rise can be normal because an Ideal combi heats water in its sealed primary circuit while producing hot
Ideal boiler radiators heat when hot water is used
← Back to Boiler Help & Advice Ideal boiler radiators heat when hot water is used If radiators warm whenever you open a hot tap, first establish whether the heating was genuinely off and whe
Ideal boiler works after reset then locks out again
← Back to Boiler Help & Advice If an Ideal boiler works after a reset and then locks out again, the reset has cleared the displayed stop condition temporarily; it has not repaired the cause.
Ideal C0 fault code explained
← Back to Boiler Help & Advice The Ideal C0 fault code means BCC activation fault. That is the exact description in Ideal’s current homeowner fault-code guidance. BCC is part of the boiler’s
Ideal C2 fault code explained
← Back to Boiler Help & Advice Ideal C2 fault code explained If your Ideal boiler is showing C2, Ideal Heating’s published fault-code guidance identifies it as a BCC Chip fault. This points
Ideal F0 fault code explained
← Back to Boiler Help & Advice Ideal boiler fault code F0 is described in Ideal Heating’s current fault-code guidance as “No Water Flow Thermistor”. The boiler has detected a problem involvi
Ideal F1 fault code explained
← Back to Boiler Help & Advice Ideal F1 fault code explained An Ideal boiler showing F1 is reporting low water pressure in the central-heating system. On Ideal models whose instructions use
Ideal F2
← Back to Boiler Help & Advice An Ideal F2 fault code means flame loss on the Ideal boiler models covered by the manufacturer guides referenced below. The boiler has not been able to maintai
Ideal F2 fault code explained
← Back to Boiler Help & Advice An Ideal F2 fault code means the boiler has lost its flame or has been unable to keep it established. Ideal describes F2 as “flame loss” in its current fault-c
Ideal F3 fault code explained
← Back to Boiler Help & Advice An Ideal F3 code commonly means a fan fault—but not on every Ideal boiler. Ideal’s current general fault-code guidance and several Logic-family manuals use F3
Ideal F4 fault code explained
← Back to Boiler Help & Advice The Ideal F4 fault code means a flow thermistor fault. On some Ideal boilers the related display may be L4 rather than F4. The flow thermistor is a temperature
Ideal F5 fault code explained
← Back to Boiler Help & Advice Ideal F5 fault code explained On the Ideal boiler ranges identified in the manufacturer’s current guidance, F5 means a return-thermistor fault. The return ther
Ideal F6 fault code explained
← Back to Boiler Help & Advice The Ideal F6 fault code means an outside sensor fault. The boiler is not receiving a valid signal from an outdoor temperature sensor or its associated circuit.
Ideal F7 fault code explained
← Back to Boiler Help & Advice The Ideal F7 fault code means low mains voltage. The boiler has detected that its electrical supply is below the level expected for reliable operation. Ideal’s
Ideal F8 fault code explained
← Back to Boiler Help & Advice Ideal F8 fault code explained If your Ideal boiler shows F8, the meaning depends on the precise model. Current Ideal manuals for the Instinct2 and Exclusive2 d
Ideal F9 fault code explained
← Back to Boiler Help & Advice The Ideal F9 fault code points to a boiler control-board fault or configuration problem. On the Logic Combi ESP1, Ideal describes F9/L9 as an unconfigured PCB.
Ideal FA fault code explained
← Back to Boiler Help & Advice The Ideal FA fault code means a negative differential between the flow and return temperature readings. Ideal’s Logic Combi ESP1 user guide describes it as “Ne
Ideal FU fault code explained
← Back to Boiler Help & Advice The Ideal FU fault code means the temperature difference between the boiler’s flow and return has exceeded 50°C. Ideal describes it as “Flow/Return Differentia
Ideal L2 fault code explained
← Back to Boiler Help & Advice Ideal L2 fault code: what it means and what to do Ideal fault code L2 means flame loss or ignition lockout. The boiler tried to light, or could not maintain a
Ideal L3 fault code explained
← Back to Boiler Help & Advice Ideal L3 fault code explained If your Ideal boiler flashes L and 3, Ideal Heating describes the fault as no water flow. The boiler expects heating water to mov
Ideal L4 fault code explained
← Back to Boiler Help & Advice Ideal L4 indicates a flow-thermistor fault on the Ideal models covered by the manufacturer documents checked for this article. Some displays show F4 or F04 ins
Ideal L6 fault code explained
← Back to Boiler Help & Advice The Ideal L6 fault code means false flame lockout. The boiler’s safety controls are detecting a flame-related signal when a normal flame should not be present.
L2-Ideal boiler ignition lockout : safe checks before calling an engineer
← Back to Boiler Help & Advice An Ideal boiler ignition lockout means the appliance tried to light but could not establish safe operation. On most Ideal models, the display commonly shows L2
Landlord gas safety certificates: a plain-English UK guide
← Back to Boiler Help & Advice If you let a property with gas appliances, you normally need an annual gas safety check carried out by a suitably qualified Gas Safe registered engineer. You m
Landlord responsibilities when a boiler breaks down
← Back to Boiler Help & Advice When a rented home’s boiler breaks down, the landlord is normally responsible for restoring the heating and hot water. The tenant should report the fault promp
Main boiler E133 fault code explained
← Back to Boiler Help & Advice Main boiler error E133 means the appliance has locked out because the gas supply was interrupted, ignition failed or a flame was not detected. Main’s current e
Main boiler E20 fault code explained
← Back to Boiler Help & Advice A Main boiler showing E20 has detected a fault in the central-heating temperature-sensor circuit on models that use this code. It normally needs professional d
Main E110 fault code explained
← Back to Boiler Help & Advice Main E110 fault code explained If a Main boiler shows E110, Baxi’s official fault-code table gives two related meanings: the boiler’s maximum temperature has b
Main E118 fault code explained
← Back to Boiler Help & Advice Main E118 fault code explained E118 on a Main Eco Compact boiler means the heating-system water pressure is low. Baxi’s official fault-code table lists E118 fo
Main E125 fault code explained
← Back to Boiler Help & Advice Main E125 fault code explained E125 on a Main boiler means a water circulation fault, according to Baxi’s official error-code table. The boiler is not seeing t
Main E128 fault code explained
← Back to Boiler Help & Advice Main boiler fault code E128 means the appliance has detected flame failure during normal operation. Baxi’s current error-code reference describes E128 for the
Main E129 fault code explained
← Back to Boiler Help & Advice Main boiler fault code E129 is a flame-loss safety error. Baxi’s current official error-code table gives the full meaning as frequent loss of flame with maximu
Main E130 fault code explained
← Back to Boiler Help & Advice If your Main boiler is showing E130, the current manufacturer error-code reference describes it as the flue thermostat sensor having tripped, causing a lockout
Main E133 fault code explained
← Back to Boiler Help & Advice Main E133 means the boiler has locked out because it has not established or maintained the expected gas flame. Baxi’s current error-code reference, which inclu
Main E134 fault code explained
← Back to Boiler Help & Advice Main boiler fault code E134 is described in Baxi’s current official error-code table as “elapsed time gas valve open without gas (short request in a short peri
Main E160 fault code explained
← Back to Boiler Help & Advice Main E160 fault code explained E160 on a Main boiler means a fan fault, according to Baxi’s official error-code table. The fan is part of the boiler’s combusti
Main E20 fault code explained
← Back to Boiler Help & Advice If a Main boiler is showing E20, the current Baxi Group error-code reference describes it as a central-heating NTC sensor fault on the covered models. The sens
Main E270 fault code explained
← Back to Boiler Help & Advice Main E270 fault code explained If a Main boiler displays E270, Baxi’s current technical reference defines the code as “Dry fire”. It is a protective fault rela
Main E28 fault code explained
← Back to Boiler Help & Advice If your Main boiler is showing E28, the current manufacturer error-code table describes it as a flue NTC sensor fault on the covered models. The sensor circuit
Main E317 / 162 fault code explained
← Back to Boiler Help & Advice Main boiler fault code E317 / 162 means the appliance has detected the wrong electrical power-supply frequency, measured in hertz (Hz). Main’s current error-co
Main E317 fault code explained
← Back to Boiler Help & Advice If your Main boiler shows E317 or 162, Baxi’s current fault-code information describes it as “Wrong power supply electrical frequency (Hz)”. The boiler has det
Main E321 fault code explained
← Back to Boiler Help & Advice Main boiler fault code E321, which may also be shown as 163 on some displays, is listed by Baxi’s current official error-code reference as a domestic-hot-water
Main E384 / 164 fault code explained
← Back to Boiler Help & Advice Main fault code E384 or 164 is listed by Baxi’s current technical support guide as false flame (parasitic flame) for the model group containing the Main Eco Co
Main E384 fault code explained
← Back to Boiler Help & Advice If your Main boiler is showing E384 or 164, the official Baxi fault-code list describes it as “False flame (parasitic flame)”. In plain English, the boiler’s c
Main E385 / 165 fault code explained
← Back to Boiler Help & Advice Main fault code E385 / 165 means the boiler has detected under-voltage. Main’s current manufacturer error-code table lists this code for the Main Eco Compact C
Main E385 fault code explained
← Back to Boiler Help & Advice Main boiler fault code E385, which may also be shown as 165, is listed by Baxi as “Under voltage”. The boiler has detected that its electrical supply voltage i
Main E40 fault code explained
← Back to Boiler Help & Advice If your Main boiler is displaying E40, the current manufacturer error-code reference describes it as a return central-heating NTC sensor fault on the covered m
Main E430 / 166 fault code explained
← Back to Boiler Help & Advice Main fault code E430 / 166 means a temporary water-pressure fault on the Main Eco Compact Combi and Main Eco Compact System ranges listed in the current manufa
Main E430 fault code explained
← Back to Boiler Help & Advice If your Main boiler shows E430 or 166, Baxi’s current error-code list describes it as a “Water pressure temporary fault”. The boiler has detected a pressure co
Main Eco Compact E09 fault code: gas valve connection fault
← Back to Boiler Help & Advice The Main Eco Compact E09 fault code means a gas valve connection fault. It is an internal gas-control and electrical connection issue, so the boiler casing mus
Main Eco Compact E10 fault code: external probe fault
← Back to Boiler Help & Advice Main Eco Compact error code E10 means “External probe fault”. That is the exact wording in Baxi Heating UK’s current error-code table for the model group that
Main Eco Compact E103 fault code: Safety Assist battery exhausted
← Back to Boiler Help & Advice Main Eco Compact E103 fault code: Safety Assist battery exhausted A Main Eco Compact showing E103 is reporting that the Safety Assist battery is exhausted. Tha
Main Eco Compact E104 fault code: Safety Assist PCB fault
← Back to Boiler Help & Advice Main Eco Compact E104 fault code: Safety Assist PCB fault A Main Eco Compact displaying E104 is reporting a faulty Safety Assist PCB. That is the official desc
Main Eco Compact E107 fault code: boiler PCBs not synchronised
← Back to Boiler Help & Advice Main Eco Compact error code E107 means “PCBs not synchronised”. That is the exact wording in Baxi Heating UK’s current error-code table for the group containin
Main Eco Compact E109 fault code: precirculation alarm
← Back to Boiler Help & Advice Main Eco Compact E109 fault code: precirculation alarm The Main Eco Compact E109 fault code means “Precirculation alarm” in Baxi’s current error-code table. Th
Main Eco Compact E110 fault code: maximum temperature or safety thermostat
← Back to Boiler Help & Advice Main Eco Compact E110 fault code: maximum temperature or safety thermostat The Main Eco Compact E110 fault code has two manufacturer-listed meanings. Baxi’s cu
Main Eco Compact E118 fault code: low water pressure
← Back to Boiler Help & Advice Main Eco Compact E118 fault code: low water pressure The Main Eco Compact E118 fault code means the boiler has detected low water pressure, below 0.5 bar. That
Main Eco Compact E12 fault code: differential water flow switch open
← Back to Boiler Help & Advice Main Eco Compact error code E12 means “Differential water flow switch fault (still open)”. That is the manufacturer’s current wording for the model group conta
Main Eco Compact E125 fault code: water circulation fault
← Back to Boiler Help & Advice Main Eco Compact E125 fault code: water circulation fault The Main Eco Compact E125 fault code means “Water circulation fault” in Baxi’s current error-code tab
Main Eco Compact E128 fault code: frequent flame-loss safety error
← Back to Boiler Help & Advice Main Eco Compact E128 fault code: frequent flame-loss safety error The Main Eco Compact E128 fault code means “Safety error for frequent loss of flame” in Baxi
Main Eco Compact E129 fault code: flame-loss safety error during calibration
← Back to Boiler Help & Advice Main Eco Compact E129 fault code: flame-loss safety error during calibration The Main Eco Compact E129 fault code means “Safety error for frequent loss of flam
Main Eco Compact E13 fault code: differential water flow switch closed
← Back to Boiler Help & Advice Main Eco Compact E13 fault code: differential water flow switch closed Main Eco Compact error code E13 means “Differential water flow switch fault (still close
Main Eco Compact E130 fault code: flue thermostat sensor tripped
← Back to Boiler Help & Advice Main Eco Compact E130 fault code: flue thermostat sensor tripped The Main Eco Compact E130 fault code means “Flue thermostat sensor tripped (lockout)” in Baxi’
Main Eco Compact E133 fault code: gas supply fault
← Back to Boiler Help & Advice Main Eco Compact E133 fault code: gas supply fault The Main Eco Compact E133 fault code means “Gas supply fault” in Baxi’s current error-code table. The table
Main Eco Compact E134 fault code: gas valve open without gas
← Back to Boiler Help & Advice Main Eco Compact E134 fault code: gas valve open without gas If your Main Eco Compact is showing E134, the boiler has stopped because its controls have recorde
Main Eco Compact E135 fault code: internal boiler error
← Back to Boiler Help & Advice Main Eco Compact E135 fault code: internal boiler error Seeing E135 on a Main Eco Compact can be frustrating because the wording is broad. Main’s current manuf
Main Eco Compact E135 fault code: internal error
← Back to Boiler Help & Advice Main Eco Compact E135 fault code: internal error If your Main Eco Compact is showing E135, the boiler has stopped after its controls recorded an internal error
Main Eco Compact E15 fault code: gas valve command fault
← Back to Boiler Help & Advice Main Eco Compact error code E15 means “Gas valve command fault”. That is the exact wording in Baxi Heating UK’s current error-code table for the model group co
Main Eco Compact E154 fault code: flow and return plausibility test
← Back to Boiler Help & Advice Main Eco Compact E154 fault code: flow and return plausibility test If your Main Eco Compact is showing E154, the boiler has stopped because its controls have
Main Eco Compact E160 fault code: fan fault
← Back to Boiler Help & Advice Main Eco Compact E160 fault code: fan fault If your Main Eco Compact is showing E160, Baxi’s current fault-code table describes it as a fan fault. The boiler h
Main Eco Compact E20 fault code: central heating NTC sensor fault
← Back to Boiler Help & Advice Main Eco Compact error code E20 means “Central heating NTC sensor fault – short circuit/open circuit”. This is the exact meaning in Baxi Heating UK’s current e
Main Eco Compact E270 fault code: dry fire
← Back to Boiler Help & Advice If your Main Eco Compact is showing E270, Baxi’s current fault-code table describes it as “Dry fire”. That is the manufacturer’s short label for the fault. It
Main Eco Compact E270 fault code: dry-fire protection
← Back to Boiler Help & Advice If your Main Eco Compact boiler shows E270, the manufacturer’s current error-code table defines it as “Dry fire.” This is a protective fault description. It me
Main Eco Compact E28 fault code: flue NTC sensor fault
← Back to Boiler Help & Advice Main Eco Compact error code E28 means “Flue NTC sensor fault – short circuit/open circuit”. That is the current wording in Baxi Heating UK’s error-code table f
Main Eco Compact E317 / 162 fault code: wrong electrical frequency
← Back to Boiler Help & Advice Main Eco Compact E317 / 162 fault code: wrong electrical frequency If your Main Eco Compact is showing E317 or 162, Baxi’s current fault-code table describes i
Main Eco Compact E317 / 162 fault code: wrong electrical supply frequency
← Back to Boiler Help & Advice Main Eco Compact E317 / 162 fault code: wrong electrical supply frequency If your Main Eco Compact boiler shows E317 / 162, the manufacturer’s current error-co
Main Eco Compact E321 / 163 fault code: domestic hot-water NTC sensor fault
← Back to Boiler Help & Advice Main Eco Compact E321 / 163 fault code: domestic hot-water NTC sensor fault A Main Eco Compact displaying E321 / 163 is reporting a domestic hot-water NTC sens
Main Eco Compact E384 / 164 fault code: false flame
← Back to Boiler Help & Advice Main Eco Compact E384 / 164 fault code: false flame If your Main Eco Compact is showing E384 or 164, Baxi’s current fault-code table describes it as “False fla
Main Eco Compact E384 / 164 fault code: false or parasitic flame
← Back to Boiler Help & Advice If your Main Eco Compact boiler shows E384 / 164, the manufacturer’s current error-code table defines it as “False flame (parasitic flame).” The boiler has det
Main Eco Compact E385 / 165 fault code: electrical under-voltage
← Back to Boiler Help & Advice Main Eco Compact E385 / 165 fault code: electrical under-voltage Main Eco Compact boilers can show E385 / 165 when the appliance detects under-voltage. Baxi’s
Main Eco Compact E385 / 165 fault code: under voltage
← Back to Boiler Help & Advice A Main Eco Compact showing E385 or 165 is reporting an under-voltage fault. Those two numbers are paired versions of the same fault on the manufacturer’s curre
Main Eco Compact E385 / 165 fault code: under-voltage supply
← Back to Boiler Help & Advice Main Eco Compact boilers may show E385 / 165 when an under-voltage condition has been detected. Baxi’s current manufacturer error-code table gives “Under volta
Main Eco Compact E40 fault code: return heating NTC sensor fault
← Back to Boiler Help & Advice Main Eco Compact error code E40 means “Return central heating NTC sensor fault – short circuit/open circuit”. This is the exact wording in Baxi Heating UK’s cu
Main Eco Compact E430 / 166 crossed-flame fault: water-pressure test failed
← Back to Boiler Help & Advice Main Eco Compact E430 / 166 crossed-flame fault: water-pressure test failed A Main Eco Compact showing E430 / 166 together with a crossed-flame symbol is repor
Main Eco Compact E430 / 166 fault code: temporary water-pressure fault
← Back to Boiler Help & Advice Main Eco Compact E430 / 166 fault code: temporary water-pressure fault A Main Eco Compact showing E430 / 166 without an extra crossed-flame symbol is reporting
Main Eco Compact E430 / 166 with crossed-flame symbol: water-pressure test failed
← Back to Boiler Help & Advice Main Eco Compact E430 / 166 with crossed-flame symbol: water-pressure test failed If your Main Eco Compact shows E430 or 166 together with a crossed-flame symb
Main Eco Compact E50 fault code: hot-water NTC sensor fault
← Back to Boiler Help & Advice Main Eco Compact error code E50 means “DHW NTC sensor fault (tank boiler) – short circuit/open circuit”. That is the current wording in Baxi Heating UK’s error
Main Eco Compact E83 fault code: communication error
← Back to Boiler Help & Advice Main Eco Compact error code E83 means “No communication”. Baxi Heating UK’s current error-code table groups E83 with E84, E85, E86 and E87 under that same word
Moving house? The boiler checks worth making
← Back to Boiler Help & Advice A boiler can look tidy during a house viewing and still leave the new owner with an expensive surprise. Before exchange, the useful questions are not simply wh
No hot water but heating works: what could be wrong?
← Back to Boiler Help & Advice If the radiators heat normally but the taps stay cold, the good news is that the boiler can still produce heat. The fault is likely to be limited to the hot-wa
One heating zone works but the other stays cold
← Back to Boiler Help & Advice One heating zone works but the other stays cold If one zone heats normally, the boiler can produce heat and at least part of the system can circulate it. The c
One radiator is much hotter than the others
← Back to Boiler Help & Advice One radiator being much hotter than the others usually points to how water is flowing around the heating system rather than a boiler fault by itself. The hotte
Potterton Assure E09 fault code: gas valve connection fault
← Back to Boiler Help & Advice Potterton Assure E09 fault code: gas valve connection fault A Potterton Assure showing E09 has detected a gas valve connection fault. That is the exact wording
Potterton Assure E107 fault code: boiler PCBs not synchronised
← Back to Boiler Help & Advice Potterton Assure E107 fault code: what “PCBs not synchronised” means The E107 fault on a Potterton Assure Combi or System boiler means the boiler’s printed cir
Potterton Assure E109 fault code: precirculation alarm
← Back to Boiler Help & Advice Potterton Assure E109 fault code: what the precirculation alarm means The E109 fault on a Potterton Assure Combi or System boiler means “Precirculation alarm”.
Potterton Assure E110 fault code: maximum temperature / safety thermostat
← Back to Boiler Help & Advice Potterton Assure E110 fault code: maximum temperature or safety thermostat E110 on a Potterton Assure Combi or System boiler is a safety-related temperature fa
Potterton Assure E12 fault code: differential water flow switch open
← Back to Boiler Help & Advice Potterton Assure E12 fault code: differential water flow switch still open Potterton Assure E12 means “differential water flow switch fault (still open)” in th
Potterton Assure E125 fault code: water circulation fault
← Back to Boiler Help & Advice Potterton Assure E125 fault code: what a water circulation fault means The E125 fault on a Potterton Assure Combi or System boiler means “Water circulation fau
Potterton Assure E128 fault code: frequent loss of flame
← Back to Boiler Help & Advice Potterton Assure E128 fault code: frequent loss of flame E128 on a Potterton Assure Combi or System boiler means “Safety error for frequent loss of flame”. The
Potterton Assure E129 fault code: flame loss during calibration
← Back to Boiler Help & Advice Potterton Assure E129 fault code: meaning, safety and repair An E129 code on a Potterton Assure means the boiler has stopped after frequent flame loss was dete
Potterton Assure E13 fault code: differential water flow switch closed
← Back to Boiler Help & Advice Potterton Assure E13 fault code: differential water flow switch closed A Potterton Assure showing E13 has detected that the differential water flow switch is s
Potterton Assure E130 fault code: flue thermostat sensor tripped
← Back to Boiler Help & Advice Potterton Assure E130 fault code: meaning, safety and next steps An E130 code on a Potterton Assure means the boiler has gone into a safety lockout after its f
Potterton Assure E134 fault code: gas valve open without gas
← Back to Boiler Help & Advice Potterton Assure E134 fault code: what it means and what to do An E134 code on a Potterton Assure means the boiler has stopped because a timed part of its gas-
Potterton Assure E135 fault code: internal error
← Back to Boiler Help & Advice Potterton Assure E135 fault code: what “internal error” means If your Potterton Assure displays E135, the official manufacturer description is simply “Internal
Potterton Assure E15 fault code: gas valve command fault
← Back to Boiler Help & Advice Potterton Assure E15 fault code: gas valve command fault A Potterton Assure showing E15 is reporting a gas valve command fault. That is the official wording in
Potterton Assure E154 fault code: flow and return plausibility
← Back to Boiler Help & Advice Potterton Assure E154 fault code: what the flow and return check means An E154 code on a Potterton Assure means the boiler has stopped because its comparison o
Potterton Assure E160 fault code: fan fault
← Back to Boiler Help & Advice Potterton Assure E160 fault code: what the fan fault means An E160 code on a Potterton Assure has a direct manufacturer description: “Fan fault.” Baxi lists it
Potterton Assure E20 fault code: central-heating NTC sensor fault
← Back to Boiler Help & Advice Potterton Assure E20 fault code: central-heating NTC sensor fault A Potterton Assure displaying E20 is reporting a central-heating NTC sensor fault. Baxi’s cur
Potterton Assure E270 fault code: dry fire
← Back to Boiler Help & Advice Potterton Assure E270 fault code: what “dry fire” means If your Potterton Assure shows E270, the boiler has recorded a dry fire fault. That is the wording used
Potterton Assure E28 fault code: flue NTC sensor fault
← Back to Boiler Help & Advice Potterton Assure E28 fault code: what it means and what to do If your Potterton Assure displays E28, the manufacturer describes it as a flue NTC sensor fault —
Potterton Assure E317 / 162 fault code: wrong electrical frequency
← Back to Boiler Help & Advice Potterton Assure E317 / 162 fault code: wrong electrical frequency E317 / 162 on a Potterton Assure is listed by the manufacturer as “Wrong power supply electr
Potterton Assure E317 / 162 fault code: wrong electrical supply frequency
← Back to Boiler Help & Advice Potterton Assure boilers may show E317 / 162 when the controls detect the wrong power-supply electrical frequency. That is the exact meaning listed in Baxi’s c
Potterton Assure E321 / 163 fault code: domestic hot-water NTC sensor fault
← Back to Boiler Help & Advice Potterton Assure E321 / 163 fault code: hot-water NTC sensor fault If your Potterton Assure displays E321 / 163, the manufacturer lists it as a domestic hot-wa
Potterton Assure E384 / 164 fault code: false flame
← Back to Boiler Help & Advice Potterton Assure E384 / 164 fault code: false flame explained If your Potterton Assure shows E384 / 164, the manufacturer describes the fault as “False flame (
Potterton Assure E384 / 164 fault code: false or parasitic flame
← Back to Boiler Help & Advice Potterton Assure boilers may show E384 / 164 when the controls register what Baxi’s current manufacturer table calls a “False flame (parasitic flame).” The mod
Potterton Assure E385 / 165 fault code: under voltage
← Back to Boiler Help & Advice Potterton Assure E385 / 165 fault code: under voltage E385 / 165 on a Potterton Assure is listed by the manufacturer as “Under voltage”. The boiler has detecte
Potterton Assure E40 fault code: return heating NTC sensor fault
← Back to Boiler Help & Advice Potterton Assure E40 fault code: what it means and what to do A Potterton Assure showing E40 has detected a return central-heating NTC sensor fault — short cir
Potterton Assure E430 / 166 fault code: temporary water-pressure fault
← Back to Boiler Help & Advice Potterton Assure E430 / 166 fault code: temporary water-pressure fault Plain E430 / 166 on a Potterton Assure is listed by the manufacturer as a “Water pressur
Potterton Assure E430 / 166 with crossed-flame symbol: water-pressure test failed
← Back to Boiler Help & Advice Potterton Assure E430 / 166 with crossed-flame symbol: water-pressure test failed On a Potterton Assure, E430 or 166 accompanied by a crossed-flame symbol has
Potterton Assure E50 fault code: hot-water NTC sensor fault
← Back to Boiler Help & Advice Potterton Assure E50 fault code: what it means and when it applies Potterton Assure E50 is listed by the manufacturer as a domestic hot-water NTC sensor fault
Potterton Assure E83 fault code: communication error
← Back to Boiler Help & Advice Potterton Assure E83 fault code: communication error A Potterton Assure showing E83 has reported a communication fault. Baxi’s current manufacturer table group
Potterton boiler E160 fault code explained
← Back to Boiler Help & Advice On applicable Potterton boilers, E160 indicates a fan fault. Because the fan is part of the boiler’s combustion and flue-safety system, this is not a homeowner
Potterton E09 fault code explained
← Back to Boiler Help & Advice Potterton E09 fault code explained If your Potterton boiler displays E09, Baxi’s current technical reference describes it as a gas valve connection fault. The
Potterton E10 fault code explained
← Back to Boiler Help & Advice Potterton E10 fault code explained If your Potterton boiler shows E10, Baxi’s current fault-code reference describes it as an external probe fault. On a compat
Potterton E110 fault code explained
← Back to Boiler Help & Advice Potterton E110 fault code explained If a Potterton boiler shows E110, Baxi’s official error-code table gives two related meanings: the boiler’s maximum tempera
Potterton E119 fault code explained
← Back to Boiler Help & Advice Potterton E119 fault code explained On Potterton models whose official guide lists E119, the code means the primary heating-system water pressure has fallen be
Potterton E125 fault code explained
← Back to Boiler Help & Advice Potterton E125 fault code explained E125 on a Potterton boiler means a water circulation fault, according to Baxi’s official error-code table. The boiler has n
Potterton E129 fault code explained
← Back to Boiler Help & Advice Potterton fault code E129 is listed by Baxi’s current official error-code reference as a safety error involving frequent flame loss during the boiler’s Calibra
Potterton E130 fault code explained
← Back to Boiler Help & Advice Potterton E130 fault code: what it means and what to do On Potterton Assure combi and system boilers, fault code E130 means the flue thermostat sensor has trip
Potterton E133 fault code explained
← Back to Boiler Help & Advice Potterton E133 means the boiler has locked out because the gas supply was interrupted, ignition failed or the flame was not detected. On some older displays th
Potterton E134 fault code explained
← Back to Boiler Help & Advice Potterton fault code E134 is a gas-valve and ignition-related safety code. Baxi’s current official table describes it as “elapsed time gas valve open without g
Potterton E160 fault code explained
← Back to Boiler Help & Advice Potterton E160 fault code explained E160 on a Potterton boiler indicates a fan fault. Baxi’s current error-code table lists this meaning for Potterton Assure C
Potterton E20 fault code explained
← Back to Boiler Help & Advice Potterton E20 fault code: what it means and what to do On a Potterton Assure combi or system boiler, fault code E20 means the boiler has detected a problem wit
Potterton E270 fault code explained
← Back to Boiler Help & Advice Potterton E270 fault code explained If your Potterton boiler is showing E270, Baxi Heating UK’s current fault-code reference defines it as “Dry fire”. This is
Potterton E28 fault code explained
← Back to Boiler Help & Advice Potterton E28 fault code: what it means and what to do On a Potterton Assure combi or system boiler, fault code E28 is listed as a flue NTC temperature-sensor
Potterton E317 / 162 fault code explained
← Back to Boiler Help & Advice Potterton fault code E317 / 162 means the boiler has detected the wrong power-supply electrical frequency, measured in hertz (Hz). Baxi Heating UK’s current of
Potterton E317 fault code explained
← Back to Boiler Help & Advice Potterton fault code E317, which may also appear as 162, is defined by Baxi as “Wrong power supply electrical frequency (Hz)” for the applicable Potterton Assu
Potterton E321 fault code explained
← Back to Boiler Help & Advice Potterton fault code E321, which may also appear as 163, is listed by Baxi as a domestic-hot-water NTC sensor fault for the Potterton Assure Combi and System g
Potterton E384 fault code explained
← Back to Boiler Help & Advice Potterton fault code E384, which may also appear as 164, is listed by Baxi as “False flame (parasitic flame)” for the Potterton Assure Combi and System ranges.
Potterton E385 / 165 fault code explained
← Back to Boiler Help & Advice Potterton fault code E385 / 165 means the boiler has detected under-voltage. Baxi Heating UK’s current error-code table includes the Potterton Assure Combi and
Potterton E385 fault code explained
← Back to Boiler Help & Advice Potterton fault code E385, also shown as 165 on applicable boilers, means “Under voltage” according to Baxi’s current error-code list. The boiler has detected
Potterton E40 fault code explained
← Back to Boiler Help & Advice Potterton E40 fault code: what it means and what to do On a Potterton Assure combi or system boiler, fault code E40 means the boiler has detected a short circu
Potterton E430 / 166 fault code explained
← Back to Boiler Help & Advice Potterton fault code E430 / 166 means a temporary water-pressure fault on Potterton Assure Combi and Potterton Assure System boilers covered by the current man
Potterton E430 fault code explained
← Back to Boiler Help & Advice If your Potterton boiler shows E430 or 166, Baxi’s current error-code list describes it as a “Water pressure temporary fault”. The boiler has detected a pressu
Potterton E50 fault code explained
← Back to Boiler Help & Advice Potterton E50 fault code explained If your Potterton boiler shows E50, Baxi’s current fault-code reference describes it as a domestic-hot-water NTC sensor faul
Potterton E83 fault code explained
← Back to Boiler Help & Advice Potterton E83 fault code explained If your Potterton boiler shows E83, Baxi’s current technical reference places it in the “no communication” group alongside E
Radiator balancing or sludge: how can you tell the difference?
← Back to Boiler Help & Advice Radiator balancing or sludge: how can you tell the difference? If some radiators heat quickly while others lag behind, the system may need balancing. If a radi
Radiator hot even when the heating is off
← Back to Boiler Help & Advice A radiator that stays warm for a short time after the heating switches off is usually just releasing stored heat. A radiator that heats up from cold while the
Radiator not working? Work out what the cold patch means
← Back to Boiler Help & Advice A radiator that is not heating properly can give useful clues before anyone reaches for a tool. Where it feels cold matters: a cold top often suggests trapped
Radiator stays cold after bleeding
← Back to Boiler Help & Advice Radiator stays cold after bleeding Bleeding helps only when trapped air is stopping hot water filling part of a radiator. If air hissed out and the radiator is
Radiator valve leaking: what should you do?
← Back to Boiler Help & Advice A leaking radiator valve may produce an occasional bead of water, a damp patch around a joint or a steady flow onto the floor. Even a slow leak matters: it can
Radiators warm up slowly after the boiler starts
← Back to Boiler Help & Advice Radiators warm up slowly after the boiler starts Radiators do not become hot the instant a boiler starts. Water must heat and circulate around the system first
Repair or replace an older boiler?
← Back to Boiler Help & Advice An older boiler does not automatically need replacing, and a repair is not automatically good value just because it costs less today. The sensible decision dep
Shower goes cold when another tap is opened
← Back to Boiler Help & Advice If your shower turns cold when somebody opens another tap, the water supply is usually being shared or disturbed faster than the system can compensate. That do
Smart thermostat overshoots the set temperature
← Back to Boiler Help & Advice Why does my smart thermostat overshoot the set temperature? A room warming slightly beyond the thermostat setting does not automatically mean the smart control
Tenants responsibilites for the heating system
← Back to Boiler Help & Advice Tenants’ responsibilities for the heating system In a rented home, the landlord is normally responsible for keeping the heating and hot-water installations in
Thermostat says heating is on but boiler is not firing
← Back to Boiler Help & Advice A thermostat can display a flame or say “heating on” without the boiler firing immediately. The symbol usually means the control is requesting heat—not that a
Upstairs radiators cold but downstairs hot
← Back to Boiler Help & Advice Upstairs radiators cold but downstairs hot When the downstairs radiators heat normally but several upstairs radiators stay cold, the boiler is clearly producin
Vaillant boiler has hot water but no heating
← Back to Boiler Help & Advice If a Vaillant combi boiler provides hot water but no central heating, the boiler can respond to tap demand but is not producing useful heat for the radiators.
Vaillant boiler hot water temperature keeps fluctuating
← Back to Boiler Help & Advice Vaillant boiler hot water temperature keeps fluctuating Hot water that repeatedly changes from warm to cool is more than an irritation, particularly in a showe
Vaillant F22 fault code explained
← Back to Boiler Help & Advice Vaillant F22 fault code explained Vaillant’s current UK fault-code guidance defines F.22 as low water pressure in the system. The boiler has made a safety shut
Vaillant F28 fault code explained
← Back to Boiler Help & Advice Vaillant F28 fault code explained Vaillant defines F.28 as a fault where the flame signal was not detected during the ignition phase. In plain English, the boi
Viessmann boiler has a red fault light
← Back to Boiler Help & Advice A red light on a Viessmann boiler means the appliance or heating system needs attention, but the light alone does not identify the fault. On some modern Vitode
Viessmann boiler pressure keeps dropping
← Back to Boiler Help & Advice A Viessmann boiler that keeps losing pressure should be investigated rather than repeatedly topped up. Viessmann identifies two broad patterns: water escaping
Viessmann boiler pressure keeps rising
← Back to Boiler Help & Advice Viessmann boiler pressure keeps rising A small rise in pressure while the heating warms up is normal. Water expands as it heats, and the boiler’s sealed system
Viessmann F4 fault code explained
← Back to Boiler Help & Advice Viessmann F4 fault code explained A Viessmann F4 code is not safe to interpret without the exact boiler model. Viessmann’s UK fault-code checker warns that the
Weather compensation- a homeowner guide
← Back to Boiler Help & Advice Weather compensation is a heating control that watches the outdoor temperature and automatically changes how hot the water sent to your radiators needs to be.
What are the legal requirements for a Carbon Monoxide Alarm?
← Back to Boiler Help & Advice What are the legal requirements for a carbon monoxide alarm? Carbon monoxide alarm rules depend on where the property is, whether it is rented, and whether a n
What counts as an emergency boiler repair?
← Back to Boiler Help & Advice A boiler problem is an emergency when it creates an immediate risk to people or property—not simply because the house is inconveniently cold. A suspected gas l
What do I do if I smell gas?
← Back to Boiler Help & Advice If you smell gas, treat it as an emergency. Do not smoke, light a flame or turn electrical switches on or off. Open doors and windows if you can do so quickly,
What does a boiler warranty actually cover?
← Back to Boiler Help & Advice A long boiler warranty can sound as though every future breakdown will be repaired free of charge. In practice, manufacturer warranties cover defined faults un
What does boiler summer mode do, and why does the boiler still fire?
← Back to Boiler Help & Advice What does boiler summer mode do, and why does the boiler still fire? Summer mode normally disables central-heating demand while leaving the boiler available fo
What information should I give a boiler engineer before a repair visit?
← Back to Boiler Help & Advice What information should I give a boiler engineer before a repair visit? Tell the engineer what is not working, when it happens, the exact display message, the
What is a boiler condensate pipe and why does it freeze?
← Back to Boiler Help & Advice A boiler condensate pipe carries away the slightly acidic water produced by a modern condensing boiler. Most of the year it works unnoticed. During prolonged f
What is a Powerflush?
← Back to Boiler Help & Advice A powerflush is a professional method of cleaning a wet central-heating system. An engineer connects a specialist flushing machine to the heating circuit and c
What is a Smart Thermostat?
← Back to Boiler Help & Advice A smart thermostat is a heating control that connects to the internet, usually through your home Wi-Fi or a separate hub. It still performs the basic job of a
What is an electric boiler?
← Back to Boiler Help & Advice What is an electric boiler? An electric boiler uses electric heating elements to warm water for radiators or underfloor heating. It can run a familiar wet cent
What is heating setback temperature and when should I use it?
← Back to Boiler Help & Advice What is heating setback temperature and when should I use it? A heating setback temperature is a lower room-temperature target used during the night or while t
What is magnatite
← Back to Boiler Help & Advice Magnetite is a black iron-oxide material produced by corrosion inside wet central-heating systems. Tiny magnetic particles can circulate in the water, settle i
What is the best way to control the heating in an HMO?
← Back to Boiler Help & Advice What is the best way to control the heating in an HMO? For most houses in multiple occupation, the best arrangement is a reliable central heating system with a
What is this brown sludge in my radiators?
← Back to Boiler Help & Advice Brown sludge or rusty-looking water from a radiator usually means the water in the central-heating system is carrying corrosion products and other debris. It i
What ISN’T included in Incredaboils Fixed Price Repair?
← Back to Boiler Help & Advice Fixed-price boiler repair is designed to make a stressful breakdown simpler: one clear price for the diagnosis, labour and covered parts needed to complete one
What setting should my Thermostatic Radiator Valves (TRV) be on?
← Back to Boiler Help & Advice What setting should thermostatic radiator valves be on? Start most occupied rooms around the middle of the dial, then adjust one step at a time until each room
What should a homeowner check after building work near a boiler flue?
← Back to Boiler Help & Advice What should a homeowner check after building work near a boiler flue? After an extension, new roof, rendering, cladding, scaffolding or other work near a boile
What should a homeowner do if rainwater is dripping near the boiler flue?
← Back to Boiler Help & Advice What should a homeowner do if rainwater is dripping near the boiler flue? Observe from a safe place, keep the flue terminal clear and arrange a check if the dr
What should a homeowner photograph when boiler pressure changes after heating?
← Back to Boiler Help & Advice What should a homeowner photograph when boiler pressure changes after heating? Photograph the pressure when the system is fully cold, again during a normal hea
What should a landlord ask a tenant to record about uneven radiators?
← Back to Boiler Help & Advice What should a landlord ask a tenant to record about uneven radiators? Ask for a short record of which rooms are affected, what the controls show, when the heat
What should a landlord consider when providing temporary heaters during a boiler repair?
← Back to Boiler Help & Advice What should a landlord consider when providing temporary heaters during a boiler repair? Temporary heaters can reduce cold while a boiler is being repaired, bu
What should a landlord do if a boiler fault happens while the tenant is away?
← Back to Boiler Help & Advice What should a landlord do if a boiler fault happens while the tenant is away? Treat the fault according to its safety and damage risk, not simply according to
What should a landlord do if a boiler fault returns after the repair was closed?
← Back to Boiler Help & Advice What should a landlord do if a boiler fault returns after the repair was closed? Treat the returning fault as a new report linked to the previous repair, not a
What should a landlord do if a boiler repair needs a second visit?
← Back to Boiler Help & Advice What should a landlord do if a boiler repair needs a second visit? A second visit is not automatically a sign that the first engineer failed. Some faults need
What should a landlord do if a tenant cannot access the boiler controls?
← Back to Boiler Help & Advice What should a landlord do if a tenant cannot access the boiler controls? Treat it as a practical heating problem, not simply a user error. Find out which contr
What should a landlord do when a boiler fault is intermittent?
← Back to Boiler Help & Advice What should a landlord do when a boiler fault is intermittent? Treat an intermittent boiler fault as an open repair until the cause has been properly assessed.
What should a landlord record after a thermostatic shower valve is replaced?
← Back to Boiler Help & Advice What should a landlord record after a thermostatic shower valve is replaced? Keep more than the invoice. A useful property record identifies the exact shower v
What should a landlord record after a water softener is serviced?
← Back to Boiler Help & Advice What should a landlord record after a water softener is serviced? Keep the service report, the softener make and model, what work was completed, the final valv
What should a landlord record after an emergency boiler repair?
← Back to Boiler Help & Advice What should a landlord record after an emergency boiler repair? Record what the tenant reported, when it was reported, how urgently it was assessed, who attend
What should a landlord record when a boiler callback is delayed?
← Back to Boiler Help & Advice What should a landlord record when a boiler callback is delayed? Record what has failed, when it was reported, the current safety position, what heating and ho
What should a landlord record when a boiler cupboard door starts vibrating?
← Back to Boiler Help & Advice What should a landlord record when a boiler cupboard door starts vibrating? A vibrating boiler-cupboard door does not identify the cause. The door, latch or hi
What should a landlord record when a boiler fault follows a water-supply interruption?
← Back to Boiler Help & Advice What should a landlord record when a boiler fault follows a water-supply interruption? Record the water-company interruption, the time supply returned, the ten
What should a landlord record when a boiler repair needs a second visit?
← Back to Boiler Help & Advice What should a landlord record when a boiler repair needs a second visit? Record what the tenant reported, who attended, what the engineer found, whether the bo
What should a landlord record when a tenant reports a boiler fault?
← Back to Boiler Help & Advice What should a landlord record when a tenant reports a boiler fault? Record when the tenant reported the problem, their exact description, whether heating or ho
What should a landlord record when a tenant reports scalding hot water?
← Back to Boiler Help & Advice What should a landlord record when a tenant reports scalding hot water? Treat the report as a potential safety hazard, not a comfort complaint. Record the exac
What should a landlord record when a tenant reports sudden shower temperature changes?
← Back to Boiler Help & Advice What should a landlord record when a tenant reports sudden shower temperature changes? Treat a sudden shower temperature change as a safety and repair report,
What should a landlord record when hot water is intermittent at only one tap?
← Back to Boiler Help & Advice What should a landlord record when hot water is intermittent at only one tap? When one tap runs hot and cold but other outlets behave normally, a clear record
What should a tenant do if a boiler engineer misses the return visit?
← Back to Boiler Help & Advice What should a tenant do if a boiler engineer misses the return visit? Tell the landlord or managing agent the same day, even if the contractor arranged the vis
What should a tenant do if communal heating fails outside office hours?
← Back to Boiler Help & Advice What should a tenant do if communal heating fails outside office hours? Use the building’s emergency repairs or heat-network number first, then tell your landl
What should a tenant include in a boiler repair complaint timeline?
← Back to Boiler Help & Advice What should a tenant include in a boiler repair complaint timeline? Put every important event in date order: when the fault began, when and how you reported it
What should a tenant record if a carbon-monoxide alarm chirps after a battery change?
← Back to Boiler Help & Advice What should a tenant record if a carbon-monoxide alarm chirps after a battery change? Write down the alarm make and exact model, the sound pattern, indicator l
What should a tenant record if a carbon-monoxide alarm stops before help arrives?
← Back to Boiler Help & Advice What should a tenant record if a carbon-monoxide alarm stops before help arrives? If a carbon-monoxide alarm sounds, treat it as a real warning even if it beco
What should a tenant record when a wireless thermostat loses connection?
← Back to Boiler Help & Advice What should a tenant record when a wireless thermostat loses connection? Record exactly what each part of the heating system shows, when the connection is lost
What should a tenant record when water tastes different after a softener service?
← Back to Boiler Help & Advice What should a tenant record when water tastes different after a softener service? Record when the change began, which taps are affected, whether the water is n
What should boiler pressure be?
← Back to Boiler Help & Advice For many sealed combi and system boilers, the pressure gauge is normally around 1 to 1.5 bar when the system is cool and rises as the heating warms, often towa
What should happen if a tenant misses a boiler repair appointment?
← Back to Boiler Help & Advice What should happen if a tenant misses a boiler repair appointment? A missed appointment should be recorded and rearranged promptly; it should not simply make t
What should I do if a boiler leak reaches electrical fittings?
← Back to Boiler Help & Advice What should I do if a boiler leak reaches electrical fittings? Keep away from the wet fitting and do not touch the boiler, fused spur, socket, plug or any near
What should I do if I see soot or staining near the boiler or flue?
← Back to Boiler Help & Advice What should I do if I see soot or staining near the boiler or flue? Do not ignore new soot or dark staining on or around a boiler, gas appliance or flue. HSE i
What size boiler does a UK home need?
← Back to Boiler Help & Advice The right boiler size is the output that meets your home’s calculated heat loss and hot-water demand without being unnecessarily oversized. It is measured in k
What temperature should a condensing boiler flow be set to?
← Back to Boiler Help & Advice What temperature should a condensing boiler flow be set to? For a modern combi boiler, 60°C is a sensible starting point for the radiator flow temperature in m
What temperature should my house be?
← Back to Boiler Help & Advice For most households, a room thermostat setting between 18°C and 21°C is a sensible starting point. The right number is the lowest temperature that keeps the pe
What temperature should my work be?
← Back to Boiler Help & Advice There is no single legal temperature for every UK workplace, but indoor workplaces must be kept at a reasonable temperature during working hours. HSE guidance
Whats the difference between the Main eco, baxi 600/800 and the potterton?
← Back to Boiler Help & Advice What’s the difference between Main Eco, Baxi 600, Baxi 800 and Potterton boilers? Main, Baxi and Potterton names often appear together because they sit within
whats the point in servicing a new/ nearly new boiler?
← Back to Boiler Help & Advice A one-year-old boiler can feel too new to need attention. It may heat the house perfectly, show no fault code and still be covered by a long manufacturer warra
Which brand of boiler should I buy?
← Back to Boiler Help & Advice The best boiler brand is not a universal winner. A well-sized boiler that suits the property, is installed and commissioned properly, uses compatible controls
Which smart thermostat should I buy?
← Back to Boiler Help & Advice The best smart thermostat is not automatically the one with the longest feature list. It is the control that matches your heating system, gives your household
Which thermostat should I buy?
← Back to Boiler Help & Advice Which thermostat should I buy? The best thermostat is not automatically the cleverest one. It is the control that suits your heating system, your routine and t
Who is responsible for a broken thermostat in a rented home?
← Back to Boiler Help & Advice Who is responsible for a broken thermostat in a rented home? In England, the landlord is normally responsible when a supplied thermostat fails and the heating
Who should a tenant contact about a communal heating fault?
← Back to Boiler Help & Advice Who should a tenant contact about a communal heating fault? Start with the repair contact given by your landlord, letting agent, housing provider or building m
Why are all my radiators heating slowly?
← Back to Boiler Help & Advice Why are all my radiators heating slowly? Radiators do not become fully hot the instant the boiler starts, but a clear change in how long every room takes to wa
why are digital service records better than paper
← Back to Boiler Help & Advice Paper boiler records have served homes and landlords for years, but they have familiar weaknesses. Carbonless-copy sheets fade, service books go missing during
Why are my radiators cold at the bottom?
← Back to Boiler Help & Advice A radiator that is warm at the top but noticeably cold across the bottom is usually struggling to circulate hot water through its lower channels. Manufacturer
Why are radiator pipes hot but the radiator is cold?
← Back to Boiler Help & Advice When the pipes beside a radiator feel hot but the panel stays cold, heat has reached the radiator connection but water is not circulating through the radiator
Why do hot taps sputter when the cold taps run normally?
← Back to Boiler Help & Advice Why do hot taps sputter when the cold taps run normally? If cold taps run smoothly but hot taps spit air and water, the issue is likely on the hot-water side r
Why do I need to bleed the same radiator repeatedly?
← Back to Boiler Help & Advice If the same radiator needs bleeding again and again, the trapped gas is a symptom rather than the whole fault. A small amount of air can collect over time, par
Why do my radiator valves whistle when the heating is on?
← Back to Boiler Help & Advice Why do my radiator valves whistle when the heating is on? A radiator valve usually whistles because fast-moving water is being forced through a narrow opening.
Why do my radiators cool down before the room reaches temperature?
← Back to Boiler Help & Advice Why do my radiators cool down before the room reaches temperature? Radiators do not have to stay fiercely hot throughout a heating period. Modern boilers can r
Why do my radiators heat in a different order?
← Back to Boiler Help & Advice Why do my radiators heat in a different order? Radiators do not normally become hot at exactly the same moment. The water has different distances and restricti
Why do my smart thermostat batteries keep running out?
← Back to Boiler Help & Advice Why do my smart thermostat batteries keep running out? Smart thermostat batteries that last days or weeks instead of their normal service life are usually a sy
Why do the household lights flicker when the boiler starts?
← Back to Boiler Help & Advice Why do the household lights flicker when the boiler starts? If the lights dip or flicker at the same moment the boiler starts, the timing suggests an electrica
Why does a boiler cupboard become hotter after storage is added?
← Back to Boiler Help & Advice Why does a boiler cupboard become hotter after storage is added? Boxes, towels and household supplies can reduce the open space around a boiler and trap warm a
Why does a boiler cupboard door whistle when the heating runs?
← Back to Boiler Help & Advice Why does a boiler cupboard door whistle when the heating runs? A cupboard door that whistles only while the heating is running is often reacting to moving air
Why does a boiler cupboard smell stronger after the door is closed?
← Back to Boiler Help & Advice Why does a boiler cupboard smell stronger after the door is closed? Closing a cupboard reduces the exchange of air with the room, so an existing odour can seem
Why does a boiler fan keep running briefly after hot water stops?
← Back to Boiler Help & Advice Why does a boiler fan keep running briefly after hot water stops? A brief fan sound after a hot tap closes can be a normal post-purge or overrun. The burner ha
Why does a boiler fault appear only after several showers?
← Back to Boiler Help & Advice Why does a boiler fault appear only after several showers? A fault that appears only after several showers is a useful pattern. It may be a genuine boiler lock
Why does a boiler fault appear only during heavy rain?
← Back to Boiler Help & Advice Why does a boiler fault appear only during heavy rain? Heavy rain can expose a problem in drainage, a condensate connection, an external terminal or weatherpro
Why does a boiler fault clear after the heating has been off overnight?
← Back to Boiler Help & Advice Why does a boiler fault clear after the heating has been off overnight? A boiler fault can disappear after the appliance and heating system have been off for s
Why does a boiler hot-water symbol stay on after the tap closes?
← Back to Boiler Help & Advice Why does a boiler hot-water symbol stay on after the tap closes? A tap or hot-water symbol can remain briefly after an outlet closes because the boiler is fini
Why does a boiler hum more loudly when several radiator valves close?
← Back to Boiler Help & Advice Why does a boiler hum more loudly when several radiator valves close? As thermostatic radiator valves close, they reduce the amount of hot water flowing throug
Why does a boiler lose pressure only after hot water is used?
← Back to Boiler Help & Advice Why does a boiler lose pressure only after hot water is used? On a combi boiler, the pressure gauge usually measures the sealed central-heating circuit—not the
Why does a boiler make a brief whirring sound after hot water stops?
← Back to Boiler Help & Advice Why does a boiler make a brief whirring sound after hot water stops? A short, smooth whir immediately after a hot tap closes can be the boiler’s pump or fan ru
Why does a boiler pressure reading take time to settle after heating stops?
← Back to Boiler Help & Advice Why does a boiler pressure reading take time to settle after heating stops? A sealed heating system does not become cold the moment the thermostat stops callin
Why does a boiler pump sound different after a service?
← Back to Boiler Help & Advice Why does a boiler pump sound different after a service? A change in pump sound after a boiler service is not automatically a fault. The engineer may have run t
Why does a boiler sound different when hot-water preheat is on?
← Back to Boiler Help & Advice Why does a boiler sound different when hot-water preheat is on? On combi boilers that support domestic-hot-water preheat, the appliance may run periodically to
Why does a boiler timer show the right time but ignore the schedule?
← Back to Boiler Help & Advice Why does a boiler timer show the right time but ignore the schedule? The clock can be correct while the heating still ignores the times you expected. That is b
Why does a carbon-monoxide alarm chirp only at night?
← Back to Boiler Help & Advice Why does a carbon-monoxide alarm chirp only at night? A carbon-monoxide alarm that seems to chirp only at night may be giving a low-battery, fault, extreme-tem
Why does a carbon-monoxide alarm show a fault after decorating?
← Back to Boiler Help & Advice A carbon-monoxide alarm showing a fault after decorating needs attention. Dust, paint mist and solvent vapours can affect an alarm, but the timing alone does n
Why does a combi boiler deliver less hot-water flow on very cold mornings?
← Back to Boiler Help & Advice Why does a combi boiler deliver less hot-water flow on very cold mornings? A combi boiler heats mains water as you use it. On a very cold morning, the incoming
Why does a combi boiler take longer to deliver hot water in winter?
← Back to Boiler Help & Advice Why does a combi boiler take longer to deliver hot water in winter? A combi boiler heats incoming mains water as it is used. In winter that water and the pipew
Why does a combi flow test change between winter and summer?
← Back to Boiler Help & Advice Why does a combi flow test change between winter and summer? The same combi boiler can appear to deliver a stronger hot-water flow in summer than in winter wit
Why does a combi shower feel stronger later in the day?
← Back to Boiler Help & Advice Why does a combi shower feel stronger later in the day? A mains-fed shower supplied by a combi boiler can feel stronger at one time of day than another. The us
Why does a combi stay steady at a tap but cycle at the shower?
← Back to Boiler Help & Advice Why does a combi stay steady at a tap but cycle at the shower? Because the tap and shower do not present the same demand. A plain hot tap may provide a stronge
Why does a heating programmer keep the clock but lose its schedule?
← Back to Boiler Help & Advice Why does a heating programmer keep the clock but lose its schedule? The clock and the heating schedule are different pieces of information. A programmer can sh
Why does a heating programmer lose only the clock but keep its schedule?
← Back to Boiler Help & Advice Why does a heating programmer lose only the clock but keep its schedule? The clock and the schedule may be stored in different ways. A programmer can retain it
Why does a heating programmer return to factory times?
← Back to Boiler Help & Advice Why does a heating programmer return to factory times? A programmer can return to its factory schedule after a deliberate reset, an interrupted setup or a faul
Why does a heating programmer show the wrong day after a power cut?
← Back to Boiler Help & Advice Why does a heating programmer show the wrong day after a power cut? A power cut can stop the clock in a heating programmer. When electricity returns, some cont
Why does a heating programmer show the wrong day but the right time?
← Back to Boiler Help & Advice Why does a heating programmer show the wrong day but the right time? The clock and weekday are separate settings on many heating programmers. A power event, ma
Why does a hot-water cylinder reheat after only a small amount is used?
← Back to Boiler Help & Advice Why does a hot-water cylinder reheat after only a small amount is used? Using a little hot water lets the same volume of cold water enter the cylinder. If that
Why does a hot-water cylinder stay warm after the boiler stops?
← Back to Boiler Help & Advice Why does a hot-water cylinder stay warm after the boiler stops? Usually because that is exactly what the cylinder is designed to do. It stores a large volume o
Why does a kitchen tap pulse when the washing machine fills?
← Back to Boiler Help & Advice Why does a kitchen tap pulse when the washing machine fills? A washing machine usually fills in short controlled bursts rather than taking water continuously.
Why does a little-used tap spit air before water flows?
← Back to Boiler Help & Advice Why does a little-used tap spit air before water flows? A tap that has not been used for a while may cough, hiss or spit briefly before the water settles into
Why does a radiator get hot only when the heating first starts?
← Back to Boiler Help & Advice Why does a radiator get hot only when the heating first starts? A radiator that heats at startup and then cools is often responding normally to the controls. I
Why does a radiator knock when its thermostatic valve closes?
← Back to Boiler Help & Advice Why does a radiator knock when its thermostatic valve closes? A knock or hammer as a thermostatic radiator valve closes is usually caused by a sudden change in
Why does a radiator make the wall or floor vibrate?
← Back to Boiler Help & Advice Why does a radiator make the wall or floor vibrate? A radiator can pass vibration into the building through its brackets and connected pipes. The original move
Why does a radiator pipe click where it passes through a wall?
← Back to Boiler Help & Advice Why does a radiator pipe click where it passes through a wall? A light click from the point where a heating pipe enters a wall is often caused by thermal movem
Why does a radiator smell dusty when heating starts?
← Back to Boiler Help & Advice Why does a radiator smell dusty when heating starts? A mild dusty smell when the heating first comes on is often caused by settled dust warming on the radiator
Why does a radiator stay warm after the heating is turned off?
← Back to Boiler Help & Advice Why does a radiator stay warm after the heating is turned off? A radiator does not cool the instant the heating switches off. Hot water and metal keep releasin
Why does a radiator stay warm after the heating switches off?
← Back to Boiler Help & Advice Why does a radiator stay warm after the heating switches off? A radiator does not become cold the moment the heating switches off. Hot water and metal hold hea
Why does a radiator valve click when the room reaches temperature?
← Back to Boiler Help & Advice Why does a radiator valve click when the room reaches temperature? A click that happens just as a room becomes warm can coincide with a thermostatic radiator v
Why does a radiator valve whistle near its lowest setting?
← Back to Boiler Help & Advice Why does a radiator valve whistle near its lowest setting? A thermostatic radiator valve often makes its smallest opening when the room is close to the tempera
Why does a radiator warm up when only hot water is selected?
← Back to Boiler Help & Advice Why does a radiator warm up when only hot water is selected? A little warmth in a nearby pipe or radiator just after the heating has run can be leftover heat.
Why does a room cool quickly after guests leave?
← Back to Boiler Help & Advice Why does a room cool quickly after guests leave? People, lighting, televisions and cooking all add heat to a home. A busy room can therefore reach its thermost
Why does a shower cool when a toilet is flushed?
← Back to Boiler Help & Advice Why does a shower cool when a toilet is flushed? Flushing a toilet starts its cistern refilling with cold water. If the shower and toilet share a restricted ma
Why does a shower pump run briefly after the shower is turned off?
← Back to Boiler Help & Advice Why does a shower pump run briefly after the shower is turned off? A shower pump that continues for a few seconds after you close the shower may simply be comp
Why does a shower pump start when a basin tap opens?
← Back to Boiler Help & Advice Why does a shower pump start when a basin tap opens? The basin may be intentionally connected to the same boosted pipework as the shower. A pump reacts to wate
Why does a shower pump start when a bath tap is opened?
← Back to Boiler Help & Advice Why does a shower pump start when a bath tap is opened? A pump sold or described as a “shower pump” may serve more than the shower. If the bath tap is connecte
Why does a shower pump start when a nearby tap is opened?
← Back to Boiler Help & Advice Why does a shower pump start when a nearby tap is opened? Usually because the pump responds to water movement or a pressure change, not to the name of the outl
Why does a shower start hot then cool on its eco spray setting?
← Back to Boiler Help & Advice Why does a shower start hot then cool on its eco spray setting? An eco spray setting changes the shower’s flow or spray pattern. On a combi-fed mixer shower, t
Why does a smart radiator valve click after the heating stops?
← Back to Boiler Help & Advice Why does a smart radiator valve click after the heating stops? A brief click after the heating stops can be the smart radiator valve finishing a commanded move
Why does a smart thermostat show heating on when the boiler is quiet?
← Back to Boiler Help & Advice Why does a smart thermostat show heating on when the boiler is quiet? On many smart systems, “heating on” means that a room or zone is requesting heat. It does
Why does a smart thermostat take several minutes to start the boiler?
← Back to Boiler Help & Advice Why does a smart thermostat take several minutes to start the boiler? A short delay can be normal. The request may travel from an app to the thermostat or rece
Why does a tap bang when it is turned off quickly?
← Back to Boiler Help & Advice Why does a tap bang when it is turned off quickly? A sharp bang immediately after a tap closes is commonly caused by a sudden change in water flow. The moving
Why does a thermostat reading change after the curtains close?
← Back to Boiler Help & Advice Why does a thermostat reading change after the curtains close? Closing curtains changes air movement between the window, wall and room. If a thermostat is besi
Why does a wireless thermostat disconnect at the same time each day?
← Back to Boiler Help & Advice Why does a wireless thermostat disconnect at the same time each day? A repeatable time is valuable evidence. It suggests that something changes on a schedule:
Why does a wireless thermostat disconnect when an extractor fan runs?
← Back to Boiler Help & Advice Why does a wireless thermostat disconnect when an extractor fan runs? If a wireless thermostat repeatedly loses connection when an extractor fan starts, the ti
Why does a wireless thermostat reconnect after a manual temperature change?
← Back to Boiler Help & Advice Why does a wireless thermostat reconnect after a manual temperature change? Because pressing a button or turning the control often creates a fresh event for th
Why does a wireless thermostat reconnect after the heating schedule has started?
← Back to Boiler Help & Advice Why does a wireless thermostat reconnect after the heating schedule has started? The schedule itself does not normally repair a wireless link. It changes the t
Why does an airing cupboard feel warmer after hot water reheats?
← Back to Boiler Help & Advice Why does an airing cupboard feel warmer after hot water reheats? A hot-water cylinder and its nearby pipes lose a small amount of heat into the cupboard, even
Why does an electric boiler use more power on cold days?
← Back to Boiler Help & Advice Why does an electric boiler use more power on cold days? Usually because the home is losing heat faster. The colder it is outside, the larger the temperature d
Why does boiler frost protection keep coming on?
← Back to Boiler Help & Advice Why does boiler frost protection keep coming on? Boiler frost protection is designed to run the pump, and on some models fire the burner, when water inside the
Why does boiler pressure change after a long shower?
← Back to Boiler Help & Advice Why does boiler pressure change after a long shower? On a combi boiler, a long shower keeps the appliance producing hot water for an extended period. The boile
Why does boiler pressure fall only after the appliance cools?
← Back to Boiler Help & Advice Why does boiler pressure fall only after the appliance cools? Pressure in a sealed heating system normally rises as the water heats and falls again as it cools
Why does boiler pressure look different first thing in the morning?
← Back to Boiler Help & Advice Why does boiler pressure look different first thing in the morning? First thing in the morning, a sealed heating system may be at its coolest point after sever
Why does boiler pressure rise more after a long heating cycle?
← Back to Boiler Help & Advice Why does boiler pressure rise more after a long heating cycle? Water expands as it gets hotter. In a sealed central-heating system, the expansion vessel is des
Why does hot water arrive faster at the top-floor tap after a shower?
← Back to Boiler Help & Advice Why does hot water arrive faster at the top-floor tap after a shower? The shower may have already filled a shared section of hot-water pipe with recently heate
Why does hot water arrive quickly at one tap but slowly at another?
← Back to Boiler Help & Advice Why does hot water arrive quickly at one tap but slowly at another? If hot water reaches one tap quickly but another takes much longer, the difference is often
Why does hot water arrive quickly in the kitchen but slowly in the bathroom?
← Back to Boiler Help & Advice Why does hot water arrive quickly in the kitchen but slowly in the bathroom? The bathroom is often farther from the boiler or hot-water cylinder than the kitch
Why does hot water change temperature after a toilet flushes?
← Back to Boiler Help & Advice Why does hot water change temperature after a toilet flushes? A toilet cistern draws cold water while it refills. If that refill shares part of the supply rout
Why does hot water cool when a washing machine fills?
← Back to Boiler Help & Advice Why does hot water cool when a washing machine fills? A modern washing machine normally fills from the cold mains. When it opens its inlet valve, it creates an
Why does hot water feel hotter at night?
← Back to Boiler Help & Advice Why does hot water feel hotter at night? Hot water should not become dangerously hot simply because it is nighttime. It may feel hotter because fewer taps and
Why does hot water go lukewarm when the heating turns on?
← Back to Boiler Help & Advice Why does hot water go lukewarm when the heating turns on? Hot water should not suddenly become unusably cool just because the central heating starts. On a comb
Why does hot water look cloudy then clear in a glass?
← Back to Boiler Help & Advice Why does hot water look cloudy then clear in a glass? Cloudy or milky-looking hot water that becomes clear from the bottom of a glass upwards is usually full o
Why does hot water pressure change during the day?
← Back to Boiler Help & Advice Why does hot water pressure change during the day? Hot-water flow can change during the day because the incoming mains supply is under greater demand, another
Why does hot water pulse at the tap?
← Back to Boiler Help & Advice Why does hot water pulse at the tap? Hot water that repeatedly changes between a strong and weak flow can be caused by the tap or shower, changing mains-water
Why does hot water reach an upstairs basin faster than the shower?
← Back to Boiler Help & Advice Why does hot water reach an upstairs basin faster than the shower? Two outlets in the same bathroom do not necessarily share the same final pipe route or flow.
Why does hot water run warm before becoming properly hot?
← Back to Boiler Help & Advice Why does hot water run warm before becoming properly hot? Hot water often starts cool or warm because the water already sitting in the pipe must leave first, a
Why does hot water splutter after the home has been empty?
← Back to Boiler Help & Advice Why does hot water splutter after the home has been empty? Brief spluttering can happen when an unused outlet or pipe run contains air, especially if the water
Why does hot water splutter after the mains supply returns?
← Back to Boiler Help & Advice Why does hot water splutter after the mains supply returns? After a mains water interruption, air can enter the supply pipes as they empty and refill. That air
Why does hot water take longer after the boiler has been idle?
← Back to Boiler Help & Advice Why does hot water take longer after the boiler has been idle? After a long idle period, a combi boiler and the water in the hot pipework have cooled. When you
Why does hot water take longer after the boiler has been off?
← Back to Boiler Help & Advice Why does hot water take longer after the boiler has been off? Hot water can take longer to arrive after a combi boiler has been idle because the water sitting
Why does hot water take longer to arrive after a kitchen extension?
← Back to Boiler Help & Advice Why does hot water take longer to arrive after a kitchen extension? The new tap is usually farther from the boiler or cylinder, so the pipe between them holds
Why does hot water take longer to reach a tap on the top floor?
← Back to Boiler Help & Advice Why does hot water take longer to reach a tap on the top floor? The usual reason is distance. Before freshly heated water can reach a top-floor tap, the cooler
Why does hot water take longer to reach upstairs taps?
← Back to Boiler Help & Advice Why does hot water take longer to reach upstairs taps? An upstairs tap is often farther from the boiler or hot-water cylinder, so more cooled water has to leav
Why does hot water take longer to warm up in winter?
← Back to Boiler Help & Advice Why does hot water take longer to warm up in winter? Hot water can take longer to arrive or reach its usual temperature in winter because the incoming mains wa
Why does hot water take longer when another tap was just used?
← Back to Boiler Help & Advice Why does hot water take longer when another tap was just used? If hot water is slower to arrive just after another tap has been used, the useful question is wh
Why does hot water temperature drop when another tap opens?
← Back to Boiler Help & Advice Why does hot water temperature drop when another tap opens? If hot water becomes cooler when another tap opens, the two outlets are usually sharing a limited s
Why does hot-water flow pulse or surge from my combi boiler?
← Back to Boiler Help & Advice Why does hot-water flow pulse or surge from my combi boiler? A combi should normally deliver a reasonably steady stream when one hot tap is held at a fixed pos
Why does my Baxi boiler keep locking out?
← Back to Boiler Help & Advice A Baxi boiler locks out when its controls detect a condition that prevents safe or reliable operation. One reset may restore operation after a temporary event,
Why does my boiler come on briefly during the night?
← Back to Boiler Help & Advice Why does my boiler come on briefly during the night? A boiler that starts briefly at night is not automatically faulty. A heating or hot-water schedule, frost
Why does my boiler condensate pump keep running?
← Back to Boiler Help & Advice Why does my boiler condensate pump keep running? A condensate pump should normally run only when enough water has collected in its reservoir. It then stops aft
Why does my boiler cupboard feel unusually warm?
← Back to Boiler Help & Advice Why does my boiler cupboard feel unusually warm? Some warmth is normal while a boiler is running, especially in a small cupboard. What matters is whether the c
Why does my boiler filling loop drip after topping up?
← Back to Boiler Help & Advice Why does my boiler filling loop drip after topping up? A small amount of water left in a removable filling hose can spill when it is disconnected. A drip that
Why does my boiler fire when no heating or hot water is on?
← Back to Boiler Help & Advice Why does my boiler fire when no heating or hot water is on? A boiler that starts briefly when no tap is open and the room thermostat is not asking for heat is
Why does my boiler flue produce more white vapour on cold days?
← Back to Boiler Help & Advice Why does my boiler flue produce more white vapour on cold days? A white plume from a modern condensing boiler is often water vapour becoming visible as warm, m
Why does my boiler hot-water temperature change with the seasons?
← Back to Boiler Help & Advice Why does my boiler hot-water temperature change with the seasons? With a combi boiler, hot water may feel cooler or flow more slowly in winter because the wate
Why does my boiler hum when the heating and hot water are off?
← Back to Boiler Help & Advice Why does my boiler hum when the heating and hot water are off? A quiet hum after the heating or hot water stops can be normal for a short time. Some boilers ke
Why does my boiler keep losing pressure?
← Back to Boiler Help & Advice A boiler that loses pressure once after radiators have been bled may simply need topping up. A boiler that needs regular repressurising is different: water may
Why does my boiler keep resetting itself?
← Back to Boiler Help & Advice A boiler that appears to keep resetting itself may actually be repeatedly losing power, entering a safety lockout, or stopping and restarting normally as heati
Why does my boiler keep running after I turn the hot tap off?
← Back to Boiler Help & Advice Why does my boiler keep running after I turn the hot tap off? A boiler can sound as though it is still running for a short time after a hot tap closes. On many
Why does my boiler keep switching between heating and hot water?
← Back to Boiler Help & Advice Why does my boiler keep switching between heating and hot water? On a combi boiler, switching from radiator heating to tap hot water is normally intentional. H
Why does my boiler keep turning itself off?
← Back to Boiler Help & Advice A boiler that appears to turn itself off may be operating normally, obeying its controls or entering a safety lockout. The important distinction is whether it
Why does my boiler keep turning itself on and off?
← Back to Boiler Help & Advice A boiler that turns on, runs briefly, switches off and starts again may be working normally—or it may be short cycling. The difference is in the timing, the he
Why does my boiler lock out only on very cold mornings?
← Back to Boiler Help & Advice Why does my boiler lock out only on very cold mornings? A lockout after a freezing night often points to something affected by low temperature. An external con
Why does my boiler make a clicking noise before it starts?
← Back to Boiler Help & Advice Why does my boiler make a clicking noise before it starts? A brief click or short burst of rapid clicking can be part of a boiler’s normal start-up. Relays swi
Why does my boiler make a ticking noise after the burner stops?
← Back to Boiler Help & Advice Why does my boiler make a ticking noise after the burner stops? A few light ticks after the burner stops can come from hot metal and pipework cooling and contr
Why does my boiler make a whooshing noise when the burner starts?
← Back to Boiler Help & Advice Why does my boiler make a whooshing noise when the burner starts? A brief, soft rush of air as a boiler starts can be the fan and burner beginning their normal
Why does my boiler only fire when the thermostat is set much higher?
← Back to Boiler Help & Advice Why does my boiler only fire when the thermostat is set much higher? A room thermostat should call for heat when its measured temperature is below the target,
Why does my boiler only make a noise when it is windy?
← Back to Boiler Help & Advice Why does my boiler only make a noise when it is windy? A noise that appears only during gusty weather may be coming from the boiler’s external flue terminal, n
Why does my boiler pressure change when I use the shower?
← Back to Boiler Help & Advice Why does my boiler pressure change when I use the shower? On a combi boiler, running a shower creates a hot-water demand inside the appliance. The boiler’s sea
Why does my boiler pressure change when the weather turns colder?
← Back to Boiler Help & Advice Why does my boiler pressure change when the weather turns colder? Colder weather does not directly “pressurise” a sealed boiler system, but it changes the cond
Why does my boiler pressure gauge move when no heating is on?
← Back to Boiler Help & Advice Why does my boiler pressure gauge move when no heating is on? Turning central heating off does not freeze the gauge in place. Pressure can fall as previously h
Why does my boiler pressure rise before the radiators get warm?
← Back to Boiler Help & Advice Why does my boiler pressure rise before the radiators get warm? A small pressure rise can happen before you feel warmth at the radiators. The boiler starts hea
Why does my boiler pressure rise slowly when the heating is off?
← Back to Boiler Help & Advice Why does my boiler pressure rise slowly when the heating is off? On a sealed heating system, pressure normally rises while water is being heated and falls agai
Why does my boiler reset keep failing?
← Back to Boiler Help & Advice A boiler reset is meant to clear a lockout after the original problem has gone. If the reset does nothing, the same code returns, or the boiler runs briefly an
Why does my boiler rumble only when a hot tap is running?
← Back to Boiler Help & Advice Why does my boiler rumble only when a hot tap is running? If a boiler rumbles only when a hot tap is open, the sound is linked to domestic hot-water demand. Th
Why does my boiler run after the thermostat is turned down?
← Back to Boiler Help & Advice Why does my boiler run after the thermostat is turned down? Turning down the room thermostat should end that zone’s call for space heating, but it does not alw
Why does my boiler run during a frost when the heating is off?
← Back to Boiler Help & Advice Why does my boiler run during a frost when the heating is off? A boiler can run in freezing weather even when the normal heating schedule is off. Many applianc
Why does my boiler start when no radiator feels warm?
← Back to Boiler Help & Advice Why does my boiler start when no radiator feels warm? A boiler can make a sound or light its display before any radiator feels warm. The system may simply be a
Why does my boiler struggle when several heating zones come on together?
← Back to Boiler Help & Advice Why does my boiler struggle when several heating zones come on together? When several heating zones start together, more of the system opens and asks for heat
Why does my boiler temperature rise after the heating switches off?
← Back to Boiler Help & Advice Why does my boiler temperature rise after the heating switches off? A brief, modest rise on the boiler display after the burner stops can be normal. Heat remai
Why does my boiler temperature rise quickly then fall again?
← Back to Boiler Help & Advice Why does my boiler temperature rise quickly then fall again? The number on most boiler displays is the temperature of water leaving the boiler, not the room te
Why does my boiler timer keep losing its settings?
← Back to Boiler Help & Advice Why does my boiler timer keep losing its settings? A boiler timer can lose its settings because its electrical supply was interrupted, its backup battery or in
Why does my boiler use electricity when it is not firing?
← Back to Boiler Help & Advice Why does my boiler use electricity when it is not firing? A modern boiler can use electricity even when the burner is off. Its control board, display, thermost
Why does my heating behave differently after a radiator was removed?
← Back to Boiler Help & Advice Why does my heating behave differently after a radiator was removed? Removing a radiator changes the amount of heat your system can release and the way water t
Why does my heating behave differently after insulation was added?
← Back to Boiler Help & Advice Why does my heating behave differently after insulation was added? Insulation slows the rate at which your home loses heat. That can make rooms warm sooner, st
Why does my heating use more energy on windy days?
← Back to Boiler Help & Advice Why does my heating use more energy on windy days? Wind can push more outside air through gaps around doors, windows, floors and service openings. Your heating
Why does my hot water keep going hot and cold?
← Back to Boiler Help & Advice Hot water that repeatedly swings from hot to cold is more than an inconvenience. It can make a shower unusable and may point to a problem with the outlet, the
Why does my hot water run hot, cold, hot, cold?
← Back to Boiler Help & Advice Why does my hot water run hot, cold, hot, cold? Hot water that repeatedly turns hot, cold, hot and cold is usually losing a stable balance between water flow a
Why does my hot water smell different from the cold water?
← Back to Boiler Help & Advice Why does my hot water smell different from the cold water? If freshly drawn cold water smells normal but the hot water does not, the cause is more likely to be
Why does my Worcester Bosch boiler gurgle when the heating turns off?
← Back to Boiler Help & Advice Why does my Worcester Bosch boiler gurgle when the heating turns off? A brief water-moving sound after heating demand ends can happen while the boiler pump car
Why does one radiator cool down before the rest?
← Back to Boiler Help & Advice Why does one radiator cool down before the rest? One radiator cooling before the others is not always a fault. Its thermostatic radiator valve may have reduced
Why does one radiator cool down faster than the others?
← Back to Boiler Help & Advice Why does one radiator cool down faster than the others? One radiator cooling sooner than the others does not automatically mean it is faulty. The room may have
Why does one radiator get hot when its valve is turned down?
← Back to Boiler Help & Advice Why does one radiator get hot when its valve is turned down? A radiator does not become cold the instant its valve is turned down. It may contain hot water, th
Why does one radiator heat up when the heating is off?
← Back to Boiler Help & Advice Why does one radiator heat up when the heating is off? One radiator can stay warm briefly after the heating switches off because hot water and the pump do not
Why does one radiator make a ticking noise as it cools?
← Back to Boiler Help & Advice Why does one radiator make a ticking noise as it cools? A few light ticks after the heating switches off are often caused by metal cooling and contracting. The
Why does one radiator only heat when another is turned off?
← Back to Boiler Help & Advice Why does one radiator only heat when another is turned off? If a cold radiator starts warming when another radiator is turned down, hot water is probably takin
Why does one radiator stay warm after its room reaches temperature?
← Back to Boiler Help & Advice Why does one radiator stay warm after its room reaches temperature? A radiator does not become cold the moment a room reaches its target temperature. The metal
Why does one radiator tick only as it cools down?
← Back to Boiler Help & Advice Why does one radiator tick only as it cools down? A light ticking sound for a few minutes after the heating stops is commonly caused by metal contracting as th
Why does one radiator vibrate when another valve closes?
← Back to Boiler Help & Advice Why does one radiator vibrate when another valve closes? Closing one radiator valve changes the route available to heating water. If the pump is still circulat
Why does one tap keep dripping briefly after it is closed?
← Back to Boiler Help & Advice Why does one tap keep dripping briefly after it is closed? A few drops immediately after a tap is closed can be water already inside the spout, aerator or pull
Why does one tap run cloudy after the rest have cleared?
← Back to Boiler Help & Advice Why does one tap run cloudy after the rest have cleared? If the wider water supply has settled but one tap still looks milky, the cause may now be close to tha
Why does one tap splutter after the water supply has been restored?
← Back to Boiler Help & Advice Why does one tap splutter after the water supply has been restored? A brief splutter can be air leaving the pipework after the supply has been drained or inter
Why does the air smell when I bleed my radiators?
← Back to Boiler Help & Advice Why does the air smell when I bleed my radiators? An odd metallic, musty or stale smell at a radiator bleed valve usually comes from the small amount of trappe
Why does the boiler clock keep losing time?
← Back to Boiler Help & Advice Why does the boiler clock keep losing time? A boiler clock that gradually falls behind is different from one that resets after a power cut. Slow drift often po
Why does the boiler condensate pipe drip more when the heating is on?
← Back to Boiler Help & Advice Why does the boiler condensate pipe drip more when the heating is on? Usually because the boiler is running for longer and producing more condensate. Condensat
Why does the boiler cupboard smell dusty when heating starts?
← Back to Boiler Help & Advice Why does the boiler cupboard smell dusty when heating starts? A mild dusty smell that appears as the heating warms up can come from settled household dust on c
Why does the boiler display change when a shower pump starts?
← Back to Boiler Help & Advice Why does the boiler display change when a shower pump starts? The display may be reacting to hot-water demand, not to the shower pump as an electrical device.
Why does the boiler display stay lit overnight?
← Back to Boiler Help & Advice Why does the boiler display stay lit overnight? A boiler display that remains visible overnight usually means the appliance still has electrical power and is i
Why does the boiler display stay on when the heating is off?
← Back to Boiler Help & Advice Why does the boiler display stay on when the heating is off? A boiler display can remain lit or continue showing a temperature when the central heating is off.
Why does the boiler fault happen only when several radiators are on?
← Back to Boiler Help & Advice Why does the boiler fault happen only when several radiators are on? A boiler that works with one or two radiators but faults when more rooms call for heat is
Why does the boiler fused spur or switch feel warm?
← Back to Boiler Help & Advice Why does the boiler fused spur or switch feel warm? A boiler switch or fused spur can sometimes pick up warmth from nearby pipework, the boiler casing or a sma
Why does the boiler lose its heating schedule after a power cut?
← Back to Boiler Help & Advice Why does the boiler lose its heating schedule after a power cut? A power cut can leave the heating clock on the wrong time, return a programmer to default peri
Why does the boiler make a brief humming noise before it fires?
← Back to Boiler Help & Advice Why does the boiler make a brief humming noise before it fires? A short, steady hum just before the flame appears can be part of a boiler’s normal start-up seq
Why does the boiler make a humming noise after the heating stops?
← Back to Boiler Help & Advice Why does the boiler make a humming noise after the heating stops? A quiet, steady hum for a short time after the heating demand ends is often the pump continui
Why does the boiler make one click but not fire?
← Back to Boiler Help & Advice Why does the boiler make one click but not fire? One click can mean the boiler or a nearby control has reacted to a request for heat, but it does not prove tha
Why does the boiler pressure gauge rise when I run hot water?
← Back to Boiler Help & Advice Why does the boiler pressure gauge rise when I run hot water? On a combi boiler, opening a hot tap starts the boiler and warms part of its sealed primary circu
Why does the boiler pressure rise overnight when heating is off?
← Back to Boiler Help & Advice Why does the boiler pressure rise overnight when heating is off? A sealed heating system should not steadily gain water simply because the heating is off. A sm
Why does the boiler sound louder when an outside door is open?
← Back to Boiler Help & Advice Why does the boiler sound louder when an outside door is open? Opening an outside door changes the background noise, airflow and way sound reflects around a ha
Why does the boiler stop when a bath is being filled?
← Back to Boiler Help & Advice Why does the boiler stop when a bath is being filled? A combi boiler should normally continue heating water while a bath tap creates enough flow. If it stops b
Why does the hall feel cold while upstairs rooms overheat?
← Back to Boiler Help & Advice Why does the hall feel cold while upstairs rooms overheat? A cold hall and overheated bedrooms usually mean the heating is not being shared evenly around the h
Why does the hall thermostat cool down when the front door opens?
← Back to Boiler Help & Advice Why does the hall thermostat cool down when the front door opens? Opening an external door replaces some warm hall air with cooler outside air. If the room the
Why does the heating come on while the hot-water cylinder is reheating?
← Back to Boiler Help & Advice Why does the heating come on while the hot-water cylinder is reheating? In a home with a hot-water cylinder, the boiler can legitimately heat the cylinder and
Why does the heating start after a smart thermostat reconnects?
← Back to Boiler Help & Advice Why does the heating start after a smart thermostat reconnects? The heating may start because the thermostat has recovered its schedule, updated the time, reco
Why does the heating switch off before the house feels warm?
← Back to Boiler Help & Advice Why does the heating switch off before the house feels warm? Heating can stop while some rooms still feel cold because the timer has reached an off period, the
Why does the heating turn off before every room is warm?
← Back to Boiler Help & Advice Why does the heating turn off before every room is warm? The heating can turn off because the room thermostat has reached its chosen temperature, even though o
Why does the hot tap smell only after it has been unused?
← Back to Boiler Help & Advice Why does the hot tap smell only after it has been unused? Water left standing in a little-used hot-water pipe can develop a stale, earthy or musty smell. Warm
Why does the hot water tap splutter after plumbing work?
← Back to Boiler Help & Advice Why does the hot water tap splutter after plumbing work? A hot tap can cough, spit or release bursts of air after plumbing work because the water was turned of
Why does the room thermostat change slowly after the heating goes off?
← Back to Boiler Help & Advice Why does the room thermostat change slowly after the heating goes off? A room thermostat does not normally drop the instant the heating switches off. It measur
Why does the thermostat read warmer after a room is crowded?
← Back to Boiler Help & Advice Why does the thermostat read warmer after a room is crowded? People give off heat, so a busy living room can become warmer even when the radiators have not cha
Why does the thermostat show a different temperature from the radiator valve?
← Back to Boiler Help & Advice Why does the thermostat show a different temperature from the radiator valve? A wall thermostat and a smart radiator valve can show different temperatures beca
Why does the thermostat show heating on while the boiler is silent?
← Back to Boiler Help & Advice Why does the thermostat show heating on while the boiler is silent? A heating symbol on a thermostat usually means the control is asking for warmth. It does no
Why has my property failed its gas tightness test this year? It was ok last year.
← Back to Boiler Help & Advice Why has my property failed its gas tightness test this year when it was fine last year? A pass last year is reassuring, but it is not a lifetime guarantee. Gas
Why is a boiler louder on hot water than on heating?
← Back to Boiler Help & Advice Why is a boiler louder on hot water than on heating? A combi boiler can sound louder when a hot tap or shower runs because domestic hot water is an immediate,
Why is a boiler quieter after its annual service?
← Back to Boiler Help & Advice Why is a boiler quieter after its annual service? A boiler can sound quieter after an annual service, and that may be reassuring, but the change is not a diagn
Why is hot water discoloured at one tap but clear elsewhere?
← Back to Boiler Help & Advice Why is hot water discoloured at one tap but clear elsewhere? If only one hot tap produces discoloured water while other hot taps run clear, the problem is more
Why is hot water flow weak from my Baxi combi boiler?
← Back to Boiler Help & Advice Why is hot-water flow weak from my Baxi combi boiler? A Baxi combi heats water as it passes through the boiler, so the flow available at a hot tap depends on t
Why is my boiler condensate pipe gurgling?
← Back to Boiler Help & Advice Why is my boiler condensate pipe gurgling? A brief trickling or bubbling sound as a condensing boiler starts or stops can simply be water moving through its dr
Why is my boiler display flickering?
← Back to Boiler Help & Advice Why is my boiler display flickering? A boiler display that flickers is not always a broken screen. Some boilers deliberately flash a symbol or fault code, whil
Why is my boiler leaking water underneath?
← Back to Boiler Help & Advice Water beneath a boiler should not be ignored, even if it is only a slow drip. It may be coming from an external pipe joint, a condensate connection, a safety d
Why is my boiler making a banging noise?
← Back to Boiler Help & Advice A boiler that suddenly starts banging, knocking or clanging is telling you that something has changed, but the sound alone does not identify the failed part. I
Why is my boiler making a gurgling noise?
← Back to Boiler Help & Advice A gurgling boiler often means water and air are moving where they should not, but the location and timing matter. Gurgling as a boiler tries to start in freezi
Why is my boiler noisy after bleeding the radiators?
← Back to Boiler Help & Advice Why is my boiler noisy after bleeding the radiators? If the boiler or pipes become noisy after you bleed a radiator, the timing often points to air or a pressu
Why is my boiler pressure too high?
← Back to Boiler Help & Advice Boiler pressure normally rises a little when the heating warms because water in a sealed system expands. However, a gauge that starts high when cold, climbs ra
Why is my boiler slow to respond to the thermostat?
← Back to Boiler Help & Advice Why is my boiler slow to respond to the thermostat? A boiler does not always fire the instant a thermostat is turned up. Some controls deliberately wait, cycle
Why is my combi boiler hot water too hot?
← Back to Boiler Help & Advice Why is my combi boiler hot water too hot? Hot water from a combi boiler should be comfortable and controllable, not so hot that you cannot safely put your hand
Why is my combi boiler water only lukewarm?
← Back to Boiler Help & Advice Why is my combi boiler water only lukewarm? A combi boiler that produces warm but never properly hot water may be dealing with a simple user setting, unusually
Why is my Ideal boiler making a bubbling noise?
← Back to Boiler Help & Advice Why is my Ideal boiler making a bubbling noise? A bubbling or gurgling sound around an Ideal boiler can come from the condensate drain, water and air moving th
Why is my radiator cold at the top?
← Back to Boiler Help & Advice A radiator that is cold at the top but warm lower down usually has air trapped inside it. Air collects at the highest point and stops hot system water filling
Why is my thermostat not communicating with my boiler?
← Back to Boiler Help & Advice If your thermostat says the heating is on but the boiler stays quiet, the two devices may not be communicating. Sometimes the cause is as simple as flat batter
Why is my Towel Radiator always full of air?
← Back to Boiler Help & Advice A towel radiator that needs bleeding again and again is not simply “one of those things”. It is often the highest radiator in the house, so any air or gas movi
Why is my Worcester Bosch blue light flashing?
← Back to Boiler Help & Advice A flashing blue light on a Worcester Bosch boiler usually means the appliance is reporting a condition that needs interpreting, but the light does not have one
Why is the radiator hot but the room still feels cold?
← Back to Boiler Help & Advice Why is the radiator hot but the room still feels cold? A radiator can feel properly hot while the room remains uncomfortable. That usually means the radiator i
Why is there a drain smell near my boiler?
← Back to Boiler Help & Advice Why is there a drain smell near my boiler? A drain-like smell near a modern boiler often comes from nearby waste pipework, a sink trap or the route used by the
Will my boiler still work if the smart meter loses connection?
← Back to Boiler Help & Advice Will my boiler still work if the smart meter loses connection? Usually, yes. A smart meter losing its data connection normally means it cannot send readings au
Worcester Bosch 1017 fault code explained
← Back to Boiler Help & Advice Worcester Bosch 1017 fault code: what it means and what to do If your Worcester Bosch boiler is showing 1017, the boiler has detected that the heating-system w
Worcester Bosch 224 fault code explained
← Back to Boiler Help & Advice Worcester Bosch 224 fault code explained Worcester Bosch cause code 224 is an overheat safety condition. On current Greenstar 8000+ professional instructions i
Worcester Bosch 228 fault code explained
← Back to Boiler Help & Advice Worcester Bosch 228 fault code: what it means and what to do A 228 fault on a Worcester Bosch boiler means the control system has detected a flame signal when
Worcester Bosch 229 fault code explained
← Back to Boiler Help & Advice Worcester Bosch 229 fault code explained Worcester Bosch cause code 229 means the boiler detected a flame and then lost it while the burner was operating. It i
Worcester Bosch 281 fault code explained
← Back to Boiler Help & Advice If your Worcester Bosch boiler is showing 281, the code points to a circulation problem on the models covered by Worcester Bosch’s relevant technical literatur
Worcester Bosch 2920 fault code explained
← Back to Boiler Help & Advice Worcester Bosch 2920 fault code: what it means and what to do If a Worcester Bosch boiler shows 2920, the manufacturer describes it as a fault in flame monitor
Worcester Bosch 2948 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2948 means “No flame signal with low output” on the Greenstar 8000 Life, Greenstar 8000+ and Condens 7000 WP manuals checked for thi
Worcester Bosch 2949 fault code explained
← Back to Boiler Help & Advice If your Worcester Bosch boiler is showing fault code 2949, the boiler has recorded no flame signal while operating at high output. In plain English, the applia
Worcester Bosch 2950 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2950 means the boiler did not receive a flame signal after its starting procedure. That is the wording used in current Greenstar 100
Worcester Bosch 2951 fault code explained
← Back to Boiler Help & Advice On Worcester Bosch Greenstar 4000, Greenstar 2000 and relevant Greenstar 8000 Life service literature, fault code 2951 means the appliance has lost its flame t
Worcester Bosch 2952 fault code explained
← Back to Boiler Help & Advice If your Worcester Bosch boiler is showing fault code 2952, the boiler has detected an internal problem while checking its flame signal. In the Worcester Bosch
Worcester Bosch 2953 fault code explained
← Back to Boiler Help & Advice On the Worcester Bosch Greenstar 2000, fault code 2953 means “No flame signal with low output.” The boiler has been operating, or attempting to operate, at a l
Worcester Bosch 2954 fault code explained
← Back to Boiler Help & Advice On the Worcester Bosch Greenstar 2000, fault code 2954 means “No flame signal with high output.” The boiler expected to confirm a flame while the burner was wo
Worcester Bosch 2955 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2955 means the boiler does not support the parameters currently set for its hydraulic configuration. In plain English, the boiler’s
Worcester Bosch 2957 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2957 points to a fault within the boiler’s control or electrical system. The exact wording changes between product ranges: Worcester
Worcester Bosch 2958 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2958 means the boiler has recorded a system fault in the appliance electronics. It is a locking fault on the Greenstar 1000 and Gree
Worcester Bosch 2959 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2959 means the boiler has recorded a system fault in the appliance electronics. On the Greenstar 1000 and Greenstar 2000 documentati
Worcester Bosch 2960 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2960 means the boiler has recorded a system fault in the appliance electronics. In the Greenstar 1000 and Greenstar 2000 service inf
Worcester Bosch 2961 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2961 means the boiler is not receiving the expected signal from its fan. The manufacturer wording in the Greenstar 1000, Greenstar 2
Worcester Bosch 2962 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2962 concerns the boiler fan. On the Greenstar 1000, Greenstar 2000 and Greenstar 8000 Life manuals checked, Worcester Bosch describ
Worcester Bosch 2963 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2963 means the boiler has found a problem with the temperature information coming from its flow, or supply, sensor and heat-exchange
Worcester Bosch 2964 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2964 means the boiler has detected that the water flow rate through its heat exchanger is too low. The code is used on several Worce
Worcester Bosch 2965 fault code explained
← Back to Boiler Help & Advice Worcester Bosch 2965 fault code: what it means and what to do Worcester Bosch fault code 2965 means the boiler’s flow temperature is too high. The manufacturer
Worcester Bosch 2966 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2966 means the flow temperature inside the heat exchanger is rising too quickly. The wording appears in official Greenstar 4000, Gre
Worcester Bosch 2967 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2967 means the boiler has detected an excessive temperature difference between its flow or supply temperature sensor and the tempera
Worcester Bosch 2968 status code explained
← Back to Boiler Help & Advice Worcester Bosch code 2968 means the boiler is automatically refilling the pressure in the heating system. In the manufacturer’s current Greenstar documentation
Worcester Bosch 2969 fault code explained
← Back to Boiler Help & Advice A Worcester Bosch 2969 fault code means the boiler has reached the maximum number of automatic pressure refills allowed by its intelligent filling system. Worc
Worcester Bosch 2970 fault code explained
← Back to Boiler Help & Advice A Worcester Bosch 2970 fault code means the boiler has detected that pressure in the heating system is falling too quickly. Worcester Bosch describes it as “Pr
Worcester Bosch 2971 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2971 means the heating-system pressure is too low. Official Greenstar 4000 and Greenstar 8000-family literature uses this wording. O
Worcester Bosch 2972 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2972 means the boiler has detected that the mains voltage reaching the appliance is too low. That is the wording used in current Wor
Worcester Bosch 2973 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2973 means the boiler has detected a system fault involving its electronics or basic controller. That is the manufacturer descriptio
Worcester Bosch 2974 fault code explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2974 means the boiler has detected an internal fault. That is the concise wording used in current Greenstar 1000 and Greenstar 2000
Worcester Bosch 2980 locking fault explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2980 means the boiler has entered a super lockout after repeated resets of locking faults within a short period. Worcester Bosch tre
Worcester Bosch 2981 locking fault explained
← Back to Boiler Help & Advice Worcester Bosch fault code 2981 means the boiler is still in a super-lockout condition and needs a qualified heating engineer. On applicable models, it can app
Worcester Bosch boiler clicks but will not ignite
← Back to Boiler Help & Advice A Worcester Bosch boiler that clicks but does not ignite may be completing part of its start sequence without establishing or proving a flame. The most useful
Worcester Bosch boiler fan keeps running
← Back to Boiler Help & Advice A Worcester Bosch boiler fan may continue briefly after the flame goes out. That can be a normal purge or overrun used to clear combustion gases and manage res
Worcester Bosch boiler fires when there is no demand
← Back to Boiler Help & Advice A Worcester Bosch boiler firing when the thermostat is not asking for heat is not automatically faulty. On a combi, hot-water PreHeat can make the burner run b
Worcester Bosch boiler has no display and will not start
← Back to Boiler Help & Advice A Worcester Bosch boiler with a completely blank display and no response usually needs an electrical-supply check before ordinary boiler fault codes can help.
Worcester Bosch boiler has no hot water
← Back to Boiler Help & Advice Worcester Bosch boiler has no hot water: what should you check? If a Worcester Bosch boiler stops providing hot water, first identify whether it is a combi boi
Worcester Bosch boiler hot water works but heating does not
← Back to Boiler Help & Advice Worcester Bosch boiler hot water works but heating does not If a Worcester Bosch combi provides normal hot water but the radiators remain cold, the boiler can
Worcester Bosch boiler is leaking from the pressure relief pipe
← Back to Boiler Help & Advice Water dripping from a Worcester Bosch boiler’s pressure-relief pipe is not normal condensate. The pressure-relief valve is a safety device that releases water
Worcester Bosch boiler is slow to fire when a hot tap opens
← Back to Boiler Help & Advice Worcester Bosch boiler is slow to fire when a hot tap opens A short wait for hot water does not always mean the boiler is slow to ignite. Water already sitting
Worcester Bosch boiler keeps restarting itself
← Back to Boiler Help & Advice Worcester Bosch boiler keeps restarting itself A Worcester Bosch boiler that seems to restart may be operating normally, responding to an external control, rec
Worcester Bosch boiler leaking water: what should you do?
← Back to Boiler Help & Advice If your Worcester Bosch boiler is leaking water, turn it off and arrange a prompt professional check. Even a small drip can point to a developing fault, lower
Worcester Bosch boiler loses flame after ignition
← Back to Boiler Help & Advice Worcester Bosch boiler loses flame after ignition If a Worcester Bosch boiler lights and then loses its flame during an active demand, the sequence is differen
Worcester Bosch boiler makes a clicking noise but will not ignite
← Back to Boiler Help & Advice If a Worcester Bosch boiler clicks repeatedly but does not ignite, the sound often means it is attempting part of its start-up sequence without establishing a
Worcester Bosch boiler makes a rattling noise when starting
← Back to Boiler Help & Advice Worcester Bosch boiler makes a rattling noise when starting A rattle as a Worcester Bosch boiler starts can come from the casing area, nearby pipes, a pump or
Worcester Bosch boiler pressure drops overnight
← Back to Boiler Help & Advice Worcester Bosch boiler pressure drops overnight If a Worcester Bosch boiler is at normal pressure in the evening but noticeably lower by morning, the sealed he
Worcester Bosch boiler pressure gauge is not moving
← Back to Boiler Help & Advice If a Worcester Bosch boiler pressure gauge is not moving, do not keep adding water simply to make the needle change. First establish whether the boiler is on a
Worcester Bosch boiler pressure rises then drops when cool
← Back to Boiler Help & Advice Worcester Bosch boiler pressure rises then drops when cool A Worcester Bosch boiler’s pressure normally rises while the heating is hot and falls again as the s
Worcester Bosch boiler pressure rises when hot water runs
← Back to Boiler Help & Advice Worcester Bosch boiler pressure rises when hot water runs A small pressure increase can be normal when a combi heats its sealed primary water during a hot-wate
Worcester Bosch boiler takes several attempts to start
← Back to Boiler Help & Advice Worcester Bosch boiler takes several attempts to start A Worcester boiler that starts only after several tries may be receiving repeated demands, going through
Worcester Bosch boiler will not reset
← Back to Boiler Help & Advice If a Worcester Bosch boiler will not reset, do not keep pressing the button or repeatedly turn the power off. A reset only releases a locking fault after the u
Worcester Bosch EA fault code explained
← Back to Boiler Help & Advice A Worcester Bosch boiler showing EA has failed to confirm a flame when it expected one. On several Greenstar models, the display may alternate between EA and a
Worcester Bosch hot water goes cold after a few minutes
← Back to Boiler Help & Advice If a Worcester Bosch combi gives hot water at first and then turns cold after a few minutes, start by working out whether the problem affects one outlet or the
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