Error code
Baxi Boiler Error Code E128 (128)
Baxi defines E128 as a safety error caused by frequent flame loss. Record the exact model and code, check only external controls and whether other gas appliances appear to have supply, and try at most one manufacturer-approved reset. Repeated E128 requires a Gas Safe registered engineer.
Quick answer
E128: The boiler has recorded frequent flame loss and shut down for safety
Meaning
The boiler has recorded frequent flame loss and shut down for safety
First safe check
Record the full boiler model, the exact E128 display, and when the lockout occurs.
Stop if
E128 returns after one permitted reset
Who to call
Contact a Gas Safe registered engineer if E128 returns after one permitted reset, ignition is unstable, heating or hot water repeatedly stops, or any gas, flame-sensing, combustion, flue, wiring, or control diagnosis is required.
High severity: escalate quickly if it persists. Keep checks outside the casing and use only a manufacturer-approved reset where the manual allows it.
Fix time
A few minutes for external observations
Difficulty
Professional-only
The useful homeowner task is to record the code and symptoms for the engineer, not diagnose internal flame-loss components.
Expected outcome: A one-off interruption may clear once, but repeated E128 requires qualified diagnosis.
What does this error code mean?
Baxi's professional error-code table defines E128 as a safety error for frequent flame loss. The boiler has lit or attempted to run but has repeatedly lost the flame signal, so it locks out rather than continuing in an unsafe or unstable state.
Possible fault areas include the gas supply, flame-sensing or ignition components, combustion setup, wiring, or control electronics. Those checks are inside the boiler and are not suitable for DIY diagnosis. Keep user actions to the display, external controls, visible pressure where the exact model provides it, and one manufacturer-approved reset only if there is no smell of gas or other safety concern.
E128 belongs to the flame-loss safety family. Relevant internal systems can include gas supply control, ignition, flame sensing, combustion, flue operation, wiring, and the boiler PCB.
Symptoms users may notice
- The boiler may ignite briefly and then lock out.
- Heating or hot water may stop after repeated ignition attempts.
- E128 may return soon after a reset if the underlying flame-loss fault remains.
What users often notice
- The display may be searched as 128 even though Baxi's official code is E128.
- The boiler can appear to start before shutting down again because the flame is not being maintained or confirmed.
Why is this happening?
- Intermittent or interrupted gas supply
- Flame-sensing electrode or ignition component fault
- Combustion, flue, or gas-valve problem
- Internal wiring or boiler control fault
What this usually points to
E128 belongs to the flame-loss safety family. Relevant internal systems can include gas supply control, ignition, flame sensing, combustion, flue operation, wiring, and the boiler PCB.
How to fix this safely
- Record the full boiler model, the exact E128 display, and when the lockout occurs.
- If you smell gas, turn off the appliance if safe, avoid electrical switches or flames, leave the area, and follow the UK gas-emergency procedure.
- Check only external controls and whether another gas appliance appears to have supply, without opening the boiler or adjusting gas components.
- Try one manufacturer-approved reset only if the exact manual allows it and there is no smell of gas, overheating, leak, or electrical concern.
- If E128 returns, stop resetting and arrange a Gas Safe registered engineer.
Can I fix this myself?
NoE128 is a repeated flame-loss safety fault. External observations and one permitted reset are the limit of homeowner checks.
Safety boundary: Do not remove the casing, adjust the gas valve, clean or bend electrodes, alter combustion settings, or bypass the lockout.
What not to do
- Do not keep resetting repeated E128 lockouts.
- Do not remove the boiler casing or touch gas, ignition, flame-sensing, flue, or combustion components.
- Do not assume a flame-loss fault is safe because the boiler relights temporarily.
Common misdiagnoses
- E128 is sometimes confused with E125, which Baxi lists as a water-circulation fault.
- A successful temporary reset does not prove that the flame-loss cause has cleared.
Reset steps
- Use only the reset method in the exact Baxi model manual.
- Reset once only if there is no smell of gas, overheating, leak, or electrical concern.
- If E128 returns, leave the boiler off and contact a Gas Safe registered engineer.
Intermittent vs persistent faults
A one-off external supply interruption may clear, but E128 specifically records frequent flame loss. Any return after one permitted reset should be treated as persistent.
Manual reference
Baxi boiler error-code table and exact model manualCountry safety notes
UK
Gas boiler work should be carried out by a Gas Safe registered engineer. If you smell gas, follow the National Gas Emergency Service instructions.
When to call a heating professional
Contact a Gas Safe registered engineer if E128 returns after one permitted reset, ignition is unstable, heating or hot water repeatedly stops, or any gas, flame-sensing, combustion, flue, wiring, or control diagnosis is required.
Safety warning
Do not attempt internal gas, combustion, flame-sensing, flue, or electrical repairs. If you smell gas, follow the UK gas-emergency procedure and do not operate electrical switches or naked flames.
Useful hub links
Related flame-loss fault codes
Relevant guide
Frequently asked questions
What does Baxi boiler error code E128 mean?+
Baxi defines E128 as a safety error for frequent flame loss. The boiler has repeatedly lost or failed to confirm a stable flame.
Is Baxi 128 the same as E128?+
Yes. Users often omit the E when searching, but Baxi's official error-code table presents the fault as E128.
Can I keep resetting Baxi E128?+
No. Try at most one manufacturer-approved reset if there is no safety concern. If E128 returns, arrange qualified diagnosis.
Can I repair Baxi E128 myself?+
No. Flame sensing, ignition, gas, combustion, flue, and internal control work should be handled by a Gas Safe registered engineer.
Sources and review status
Model dependent · Last reviewed 14 July 2026
- Baxi professional boiler error-code table
manufacturer support · UK · checked 14 July 2026
Baxi defines E128 as a safety error for frequent loss of flame and lists it for several combi and system boiler ranges.
- HSE domestic gas safety guidance
government safety · UK · checked 14 July 2026
HSE guidance confirms that domestic gas-appliance work should be carried out by a competent Gas Safe registered engineer in the UK.
Model variation note
Baxi officially lists E128 for several combi and system boiler ranges. Exact reset controls and diagnostic steps vary by model, so use the model manual and leave internal testing to a Gas Safe engineer.