BoilerFaultCodes F.765 High
Boiler Fault Code F.765
Also written as F765 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.765 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 is struggling to communicate with a secondary heating unit or an additional linked appliance, causing the system to stop working as a safety precaution. (As reported on Viessmann Vitodens 222-F B2TF)
Pick your boiler brand for the F.765 fix
Source
Information for the F.765 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