Boiler Fault Code F.546

Also written as F546 — same fault.

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

Fault code F.546 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 A sensor responsible for measuring the water temperature in your second heating zone is reporting a fault, which may prevent that specific part of your heating system from warming up correctly. (As reported on Viessmann Vitodens 222-F B2TF)