BoilerFaultCodes F.85 High
Boiler Fault Code F.85
Also written as F85 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.85 appears across 2 boiler brands and 40 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler has detected that the temperature sensors are giving unusual readings, likely because they are loose or have been installed on the wrong pipes. (As reported on Vaillant ecoTEC Pro)
Pick your boiler brand for the F.85 fix
Source
Information for the F.85 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