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 boiler make and model, visible pressure, recent work and any safety concern. Add clear access, parking and contact information. Good evidence helps the engineer prepare, but you do not need to diagnose the fault yourself.

Photograph what you can see with the casing closed. Never remove panels, operate internal valves or repeat a risky fault to create evidence.

Begin with the effect on the home

Say whether you have no heating, no hot water, both, or an intermittent problem. Mention whether every radiator or hot outlet is affected or just one.

Describe what the appliance does rather than saying only that it is “broken”. For example: “The display stays on, hot water works, but the radiators remain cold.”

Give the make and exact model

The make is normally visible on the boiler front. The model may appear on a user label, manual or previous service record. Do not remove the casing to find it.

Different models use different parts, operating sequences and fault codes. Accurate identification helps the engineer bring suitable information and plan the visit.

Include the serial number if safely visible

Some repair booking systems ask for a serial number because it identifies the exact appliance version. Photograph the visible label rather than copying a long number by memory.

If the label is inside the casing, inaccessible or unclear, say so. The engineer can identify it safely during the visit.

Copy the display exactly

Record every letter, number, dot and symbol, and whether it flashes or alternates. A full photograph of the control panel provides context that a cropped code can miss.

Do not use a fault meaning found for another model as your diagnosis. Give the engineer the raw code and the appliance details.

Describe when the fault occurs

Note whether it happens from a cold start, after several minutes, during hot-water use, when several radiators open, overnight or only in freezing weather.

For intermittent faults, record two or three recent examples with dates and times. That is usually more useful than repeatedly resetting the boiler until the symptom becomes permanent.

Say what still works

Positive information narrows the search. Tell the engineer if hot water is steady while heating fails, if one tap is affected, if the fan runs, or if the boiler works after a single reset but fails later.

Also say whether the room thermostat, programmer and display have power. Do not change several settings just before the visit.

Record visible pressure and system temperature

If the boiler displays pressure, photograph it when the system is fully cool and again when the fault occurs, provided that can be done safely. State whether the number is pressure in bar or temperature in degrees.

Do not refill, bleed or drain the system merely to improve the reading before the appointment. The original pattern is useful diagnostic evidence.

List sounds, smells and visible signs

Describe a sound in ordinary language—clicking, banging, humming, whistling or gurgling—and say when it starts and stops. A short recording can help an intermittent noise.

Report leaks, staining, soot, scorch marks or unusual vapour. Do not approach a flue, touch hot pipes or deliberately recreate a dangerous condition.

Flag safety concerns first

Tell the booking team immediately if you smell gas, a carbon monoxide alarm has sounded, there is soot or anyone feels unwell with headache, dizziness, nausea or breathlessness.

Do not wait for a routine repair appointment in a gas emergency. Call the National Gas Emergency Service on 0800 111 999 and follow its instructions. Seek urgent medical advice if carbon monoxide exposure is suspected.

Mention recent work or changes

Tell the engineer about recent plumbing, radiator removal, decorating, a new thermostat, electrical work, a power cut, water interruption or previous boiler visit.

Include the date and what changed afterwards. A sequence is more helpful than assuming the earlier work caused the fault.

Share the repair and service history you have

Previous job sheets can show which parts were changed, earlier pressure or combustion readings and whether follow-up work was recommended. Keep the documents available without trying to interpret technical measurements.

If another engineer isolated the appliance or labelled it unsafe, state that clearly. Do not reconnect or use it until the stated safety issue has been resolved.

Explain the heating system layout

Say whether the home has a combi boiler, a hot-water cylinder, separate zones, underfloor heating, smart controls or a communal system if you know. Mention any controls the engineer may need to see.

If you are unsure, describe what is physically present. Do not guess or open cupboards that are unsafe to access.

Prepare access to the appliance

Clear ordinary household items from in front of the boiler, cylinder and controls. Baxi advises providing clear access around the appliance and safe access, flooring and lighting where loft work is needed.

Do not dismantle fitted cupboards or boiler boxing yourself. Tell the engineer in advance if access is tight, high up or behind stored belongings.

Provide practical visit details

Confirm the full address, postcode, best contact number and who will let the engineer in. Mention entry codes, permits, restricted parking, difficult stairs and whether keys must be collected.

Answer calls around the appointment window where possible. Manufacturer visit guidance notes that an engineer may need to call before arrival and can need nearby parking for tools and equipment.

Keep pets and the work area safe

Secure pets away from the boiler and the route to it. Keep children and other occupants out of the work area while tools and hot components are in use.

Tell the engineer about mobility, communication or household needs that affect the visit. This is practical planning, not technical diagnosis.

Check the engineer’s identity

HSE advises asking to see the engineer’s Gas Safe ID card and checking that the back lists the correct work category. Boiler repair requires the relevant current competence.

Gas Safe Register is the official list of engineers legally registered for gas work. Do not let an unregistered person remove the boiler casing or work on gas components.

What not to do before the visit

Do not remove the casing, alter gas or boiler service valves, change pump settings, open a sealed cylinder fitting or buy a part based only on an online diagnosis.

Avoid repeated resets and changing several controls. If a simple user action from the exact manual was tried once, tell the engineer what happened.

A concise message you can send

Use this structure: “Boiler make/model: __. Problem: __. Started: __. Heating: working/not working. Hot water: working/not working. Display code: __. Cold pressure: __. Happens when: __. Recent changes: __. Safety concern or leak: __. Access and contact: __.”

Add photos of the boiler front, display and any visible leak or staining. Keep the message factual and short enough to scan.

Common questions

Do I need to know the fault cause?

No. Clear observations, timings and display information are enough. Diagnosis is the engineer’s job.

Should I leave the boiler running for the engineer?

Follow the booking advice. If the appliance is suspected unsafe, has been isolated or presents an emergency, do not use it merely to demonstrate the fault.

What if the fault disappears before the visit?

Keep the appointment if advised and provide photos, video and a timeline. Intermittent faults can still be assessed.

Do I need to clear the whole room?

No, but provide a safe, unobstructed route and working space around the appliance, controls and any relevant cylinder.

Related guides: What landlords should record, Boiler works after reset then fails again and Managing an intermittent boiler fault.