BoilerFaultCodesBaxi 09 Fault Code
The Baxi 09 fault code means: your boiler has detected an issue with the temperature sensor reading, meaning it cannot safely monitor how hot the water inside is and has shut down to prevent damage.. It appears on 16 Baxi models in our database.
Technical description: Collector Temperature
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Baxi models that show the 09 fault code
Click a model for the full fault code list and model-specific repair notes.
- 124 Combi Repair: £120-£280
- 128 Combi Repair: £120-£280
- 615 System 15 Repair: £100-£250
- 618 SYSTEM Repair: £100-£250
- 624 System 24 Repair: £100-£250
- 818 System Repair: £150-300
- 824 SYSTEM Repair: £150-300
- Assure Repair: £80-120
- Duo-tec Combi GA Repair: £120-£350
- EcoBlue System Repair: £150-250
- Neta-tec Combi 24 GA
- Neta-tec Combi 28 GA
- Neta-tec Combi 33 GA
- PLATINUM COMPACT 25 COMBI Repair: £150-300
- PLATINUM COMPACT 30 COMBI Repair: £150-300
- PLATINUM COMPACT 36 COMBI Repair: £150-300
Source
Baxi 09 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