F[-] High

Boiler Fault Code F[-]

Also written as F — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code F[-] appears across 4 boiler brands and 9 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 a generic internal system error that prevents it from operating normally, and it requires a professional to diagnose the specific underlying cause. (As reported on Ideal Atlantic Combi)

Pick your boiler brand for the F[-] fix

Gledhill F[-] 1 model Ideal F[-] 5 models Pro F[-] 1 model Worcester Bosch F[-] 2 models

Source

Information for the F[-] 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 7 July 2026