BoilerFaultCodes F.65 High
Boiler Fault Code F.65
Also written as F65 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.65 appears across 1 boiler brand and 53 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler's internal computer is overheating, which has caused the system to shut down to prevent damage to the electronics. (As reported on Vaillant Turbomax Plus 828)
Pick your boiler brand for the F.65 fix
Source
Information for the F.65 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 27 April 2026