BoilerFaultCodesAlpha 05 Fault Code
The Alpha 05 fault code means: your boiler has detected a problem with the internal sensor that monitors the temperature of the water heading to your radiators, causing the system to stop running as a safety precaution.. It appears on 24 Alpha models in our database.
Technical description: CH flow sensor fault — incorrect flow sensor resistance value
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 05: no call-out fees, no surprise bills.
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Alpha models that show the 05 fault code
Click a model for the full fault code list and model-specific repair notes.
- CD18 / CD24 Repair: £120-200
- Cd50s Cd70s Repair: £250-450
- E-Tec 28 Repair: £150-250
- E-Tec 33 Repair: £150-250
- E-Tec NX Repair: £120-£210
- E-Tec NXS Repair: £90-160
- E-Tec Plus Repair: £150-250
- E-Tec Plus 10 / 18 Repair: £90-160
- E-Tec Plus 28 Repair: £150-250
- E-Tec Plus 33 Repair: £150-250
- E-Tec Plus NX Repair: £100-£180
- E-Tec Regular Repair: £150-250
- E-Tec S Repair: £90-160
- Eco Repair: £120-200
- Eco 11 13 Repair: £90-160
- Evoke Repair: £150-250
- Evoke 10 / 18 Repair: £90-160
- Evoke NX Repair: £90-160
- Intec 40GS2 Repair: £120-220
- Intec 50CS Repair: £120-220
- Intec S Repair: £120-220
- Intec2 25 28XE Repair: £150-250
- Intec2 30SE Repair: £150-250
- SY9 24 Repair: £250-450
Source
Alpha 05 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 7 July 2026