BoilerFaultCodesBaxi 109 Fault Code
The Baxi 109 fault code means: your boiler has detected that the burner has successfully lit, but this informational status code may indicate a temporary cycle monitoring check or require professional attention if it persists and locks out the system.. It appears on 17 Baxi models in our database.
Technical description: Burner lights
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 109: 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 109 fault code
Click a model for the full fault code list and model-specific repair notes.
- 124 Combi Repair: £150-£350
- 128 Combi Repair: £150-£350
- 615 System 15 Repair: £100-£250
- 618 SYSTEM Repair: £100-£250
- 624 System 24 Repair: £100-£250
- 818 System Repair: £150-350
- 824 SYSTEM Repair: £150-350
- Duo-tec Combi GA Repair: £150-£350
- EcoBlue Repair: £150-300
- Ecoblue Advance Combi Repair: £120-250
- EcoBlue System Repair: £150-350
- Neta-tec Combi 24 GA
- Neta-tec Combi 28 GA
- Neta-tec Combi 33 GA
- PLATINUM COMPACT 25 COMBI
- PLATINUM COMPACT 30 COMBI
- PLATINUM COMPACT 36 COMBI
Source
Baxi 109 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 31 August 2026