BoilerFaultCodesBaxi 128 Fault Code
The Baxi 128 fault code means: your boiler has attempted to start but failed to detect a flame, causing it to stop operating to ensure your safety.. It appears on 12 Baxi models in our database.
Technical description: Loss of flame during operation
What causes the Baxi 128 fault?
This fault occurs when the boiler successfully lights, but the internal sensors lose track of the flame while it is running, causing the system to shut down for safety. The most common reasons are a worn-out sensing probe that can no longer 'see' the fire, or an unstable gas supply that prevents the flame from staying consistent.
DIY fix possible
Check that your gas pre-pay meter has creditEnsure other gas appliances in your home are working to confirm gas supplyPress the 'Reset' button for five seconds
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Avoid the next call-out bill
A cover plan would handle faults like 128: no call-out fees, no surprise bills.
Affiliate links. We may earn a commission at no extra cost to you.
Baxi models that show the 128 fault code
Click a model for the full fault code list and model-specific repair notes.
- 124 Combi Repair: £100-280
- 200 / 400 Combi Repair: £120-250
- 600 Combi (range) Repair: £100-280
- 624 Combi Repair: £100-£350
- Assure Repair: £120-250
- Bermuda Repair: £120-£350
- EcoBlue Repair: £100-£350
- Ecoblue Advance Combi Repair: £150-300
- EcoBlue Advance Heat Repair: £100-£350
- EcoBlue Heat Repair: £100-£350
- EcoBlue Plus Combi Repair: £100-£350
- EcoBlue System Repair: £120-250
Source
Baxi 128 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026