BoilerFaultCodes Fault light is on High
Boiler Fault Code Fault light is on
Also written as FAULTLIGHTISON — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Fault light is on 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 detected a general internal error and has locked itself out for safety, meaning your heating and hot water will not work until it is reset or repaired. (As reported on Vokera Compact HE)
Pick your boiler brand for the Fault light is on fix
Source
Information for the Fault light is on 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 27 April 2026