BoilerFaultCodes C8 High
Boiler Fault Code C8
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code C8 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has stopped working because the fan that clears exhaust gases from the system is not spinning at the correct speed. (As reported on Gledhill GB35C)
Pick your boiler brand for the C8 fix
Source
Information for the C8 fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026