Boiler Fault Code Flash Off Flash

Also written as FLASHOFFFLASH — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026

Fault code Flash Off Flash appears across 2 boiler brands and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is not receiving enough electricity to work properly, which may be caused by a fault in your home's wiring or a problem with your local power supply. (As reported on Potterton Promax Heat Only)