BoilerFaultCodes Flashing Mains ON light Low
Boiler Fault Code Flashing Mains ON light
Also written as FLASHINGMAINSONLIGHT — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Flashing Mains ON light 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 is receiving power, but it has been turned off at the main control dial. (As reported on Potterton Performa System HE)
Pick your boiler brand for the Flashing Mains ON light fix
Source
Information for the Flashing Mains ON light 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