Fast Flashing (8Hz) High

Boiler Fault Code Fast Flashing (8Hz)

Also written as FASTFLASHING8HZ — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code Fast Flashing (8Hz) appears across 1 boiler brand and 4 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 an internal electrical error or a component failure during its startup sequence that is preventing it from firing up. (As reported on Glow-worm Micron 30ff)

Pick your boiler brand for the Fast Flashing (8Hz) fix

Glow-worm Fast Flashing (8Hz) 4 models

Source

Information for the Fast Flashing (8Hz) 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