BoilerFaultCodesBaxi 20 Fault Code
The Baxi 20 fault code means: your boiler has lost the ability to accurately measure the temperature of the water circulating through your heating system, so it has shut down to prevent overheating.. It appears on 26 Baxi models in our database.
Technical description: Central Heating NTC Fault
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 20 fault code
Click a model for the full fault code list and model-specific repair notes.
- 124 Combi Repair: £90-160
- 200 / 400 Combi Repair: £120-200
- 600 Combi (range) Repair: £90-160
- 624 Combi Repair: £90-160
- 630 COMBI LPG
- 636 COMBI
- 636 COMBI LPG
- 825 Combi
- Assure Repair: £150-300
- Bahama 100 Repair: £150-250
- Combi Instant 80/105 HE Repair: £120-200
- Duo-tec Combi ErP Repair: £150-300
- Duo-tec Combi GA Repair: £90-160
- Duo-tec Combi HE A Repair: £120-180
- EcoBlue Repair: £120-200
- Ecoblue 12 System ErP
- Ecoblue 15 System ErP
- Ecoblue 24 System ErP
- Ecoblue 28 System ErP
- Ecoblue Advance Combi Repair: £120-200
- EcoBlue System Repair: £120-200
- Ecoblue18 System ErP
- PLATINUM COMPACT 25 COMBI
- PLATINUM COMPACT 30 COMBI
- PLATINUM COMPACT 36 COMBI
- System 35/60 / 60/100 Repair: £120-250
Source
Baxi 20 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