Boiler Fault Code F.463

Also written as F463 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026

Fault code F.463 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 is failing to detect a stable flame because it cannot properly read the combustion mixture, causing it to shut down for safety. (As reported on Viessmann Vitodens 100-W WB1A)