BoilerFaultCodes F.477 Low
Boiler Fault Code F.477
Also written as F477 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.477 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's solar water heating system is struggling to balance temperatures correctly, meaning the solar panels aren't effectively warming your water tank right now. (As reported on Viessmann Vitodens 222-F B2TF)
Pick your boiler brand for the F.477 fix
Source
Information for the F.477 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