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.
The boiler has recorded repeated occasions when a flame was no longer detected during operation. Five recorded losses within a 24-hour period trigger this specific code. It describes a repeated pattern, not a single brief event, and it does not identify the cause or a part that should be replaced.
What does repeated flame loss mean?
A gas boiler must establish and monitor a stable flame whenever it is producing heat. Its safety controls check that combustion is present when expected. If the flame signal is lost, the boiler stops the gas supply and may attempt a controlled restart.
E.01.04 means this flame-loss event has been detected five times during the stated period. The code does not tell the homeowner whether the issue relates to the gas supply, combustion conditions, flame monitoring, electrical control or another factor. Those possibilities require professional checks.
Do not confuse this code with an ordinary shutdown after the thermostat is satisfied. E.01.04 is a recorded safety-control response to flame loss, not simply the boiler reaching the requested temperature.
Which Baxi boilers use E.01.04?
Baxi lists E.01.04 in the current Combi & System 2 error-code group. That group includes the Baxi 200, 400, 600 and 800 Combi 2 ranges, Baxi Assure 500 Combi 2, and the Baxi 600, 800 and Assure 500 System 2 ranges.
Fault-code meanings are not universal across every Baxi boiler. Confirm the complete model name on the appliance case or household paperwork before relying on this meaning. Give both the model and full code to the repair provider.
What might you notice at home?
The household effect depends on whether the appliance is a combi or system boiler and when the flame is lost. You may notice:
- E.01.04 on the boiler display;
- the boiler starting and stopping repeatedly;
- radiators warming briefly and then cooling;
- tap hot water changing temperature on a combi boiler;
- a separate cylinder failing to reheat on a system boiler;
- the code returning after the appliance appears to recover;
- heating and hot water becoming unavailable.
Record what was being requested when the code appeared, whether other gas appliances appear normal without using them as test equipment, and whether the fault is constant or intermittent.
Does E.01.04 mean the gas supply is off?
Not necessarily. A gas-supply issue is one possible category an engineer may consider, but the code does not prove it. Do not attempt to test the supply, operate gas valves repeatedly or dismantle any appliance.
If you have a prepayment gas meter, you can check the normal user display and account balance without opening or altering equipment. If the gas supply appears unavailable across the property, contact the supplier using its official advice. Do not use the boiler’s code alone to decide that the meter or network is responsible.
What can you safely check?
Keep the boiler casing closed. Note the full code, confirm the normal heating controls are requesting heat and record whether heating, tap hot water or cylinder reheating is affected. Check for any planned supply interruption reported through an official provider.
If the exact user guide for your boiler permits a reset, one reset can be tried. Because E.01.04 records repeated flame loss, do not continue resetting if the code remains or returns. Repeated restarts do not correct the underlying condition and can delay professional attention.
Make a note of recent weather, building work, gas-supply work or boiler servicing, but do not inspect the flue, burner or internal combustion parts.
What should you not do?
Do not remove the boiler case, clean or adjust combustion components, inspect electrodes, alter gas valves or interfere with the flue. Do not use a flame, tool or electrical meter to test the appliance. Do not copy an engineer procedure from a video or forum.
Do not block ventilation, cover the boiler or repeatedly switch the electrical supply off and on. The safe homeowner role is to observe, record and arrange qualified help.
When is E.01.04 urgent?
Repeated flame loss needs professional attention even when the boiler restarts, because the code shows the event has occurred several times. Arrange a repair if E.01.04 is displayed or returns. Work involving combustion or the gas appliance must be carried out by a suitably qualified Gas Safe registered engineer.
If you smell gas, avoid flames and electrical switches, open doors and windows if safe, leave the property and follow the National Gas Emergency Service instructions. If a carbon-monoxide alarm sounds or anyone has headache, dizziness, nausea, breathlessness or confusion, move into fresh air and seek urgent help.
Stop using the appliance for smoke, scorching, unusual electrical smells, visible damage or water affecting electrical equipment. The code is not itself a carbon-monoxide reading, but any independent warning takes priority.
What to tell the engineer
- the full code E.01.04;
- the exact Baxi model;
- whether the appliance is a combi or system boiler;
- whether heating, hot water or both are affected;
- whether the boiler starts before stopping;
- when the code first appeared;
- whether any supply or building work happened recently;
- whether one guide-permitted reset changed the behaviour.
This helps the engineer understand the repeated pattern without asking you to inspect combustion equipment.
Quick Answers
How many flame losses trigger E.01.04?
Baxi’s current wording states that flame loss has been detected five times in 24 hours.
Can the boiler start working again?
It may appear to recover temporarily, but the repeated events still require professional assessment if the code is displayed or returns.
Should I keep resetting it?
No. Use at most one reset when the exact model’s user guide permits it. Repeated resets are not a repair.
Can I check the burner or flame sensor?
No. Keep the casing closed. Combustion and flame-monitoring checks belong to a Gas Safe registered engineer.
Need the boiler repaired?
Your boiler fault is fixed for the agreed price, subject to eligibility and terms.