BoilerFaultCodes F.667 Medium
Boiler Fault Code F.667
Also written as F667 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.667 appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler is having trouble communicating with the sensors responsible for heating your hot water storage tank, which means your secondary hot water supply or solar heating system may not be functioning correctly. (As reported on Viessmann Vitodens 100-W WB1A)
Pick your boiler brand for the F.667 fix
Source
Information for the F.667 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