BoilerFaultCodes F.318 High
Boiler Fault Code F.318
Also written as F318 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.318 appears across 1 boiler brand and 3 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 switch between heating your radiators and heating your hot water because the internal valve that directs the water flow is not receiving an electrical signal. (As reported on Vaillant ecoTEC Plus 836)
Pick your boiler brand for the F.318 fix
Source
Information for the F.318 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