BoilerFaultCodes F.456 High
Boiler Fault Code F.456
Also written as F456 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.456 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 software error while trying to ignite, causing it to shut down for safety to prevent an uncontrolled burner sequence. (As reported on Viessmann Vitodens 222-F B2TF)
Pick your boiler brand for the F.456 fix
Source
Information for the F.456 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