BoilerFaultCodes F0b High
Boiler Fault Code F0b
Also written as F0B — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F0b appears across 1 boiler brand and 1 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 electrical fault with the internal sensor that monitors water temperature, meaning it cannot safely regulate heat and has shut down. (As reported on Viessmann Vitodens 025-W)
Pick your boiler brand for the F0b fix
Source
Information for the F0b 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