F8 High

Boiler Fault Code F8

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code F8 appears across 7 boiler brands and 41 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's internal computer has forgotten its settings or has developed a technical communication error, meaning it cannot safely control the heating process. (As reported on Ideal Logic+ System)

Pick your boiler brand for the F8 fix

Alpha F8 4 models Ferroli F8 4 models Glow-worm F8 5 models Heatline F8 6 models Ideal F8 8 models Saunier Duval F8 5 models Viessmann F8 9 models

Source

Information for the F8 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