FF Unknown

Boiler Fault Code FF

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

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

Pick your boiler brand for the FF fix

Viessmann FF 1 model Worcester Bosch FF 1 model

Source

Information for the FF 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 31 August 2026