BoilerFaultCodesAlpha 03 Fault Code
The Alpha 03 fault code means: your boiler has detected that the exhaust gases are becoming dangerously hot, so it has automatically shut itself down to prevent damage or safety hazards.. It appears on 24 Alpha models in our database.
Technical description: High flue thermostat temperature - Flue thermostat intervention (flue temperature over 113°C)
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A cover plan would handle faults like 03: no call-out fees, no surprise bills.
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Alpha models that show the 03 fault code
Click a model for the full fault code list and model-specific repair notes.
- CD18 / CD24 Repair: £120-250
- Cd50s Cd70s Repair: £150-300
- E-Tec 28
- E-Tec 33
- E-Tec NX Repair: £120-350
- E-Tec NXS Repair: £120-£350
- E-Tec Plus 28
- E-Tec Plus 33
- E-Tec Plus 38
- E-Tec Plus NX Repair: £120-350
- E-Tec Regular Repair: £150-300
- E-Tec S Repair: £120-350
- Eco Repair: £150-300
- Eco 11 13 Repair: £150-300
- Evoke Repair: £150-250
- Evoke 10 / 18 Repair: £120-300
- Evoke NX Repair: £120-£350
- Intec 30GS Repair: £150-350
- Intec 40GS Repair: £150-350
- Intec 50CS Repair: £150-350
- Intec S Repair: £150-300
- Intec² 20SE Repair: £150-300
- Intec2 25 28XE Repair: £150-300
- Intec² 30SE Repair: £150-300
Source
Alpha 03 fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026