BoilerFaultCodes F.338 High
Boiler Fault Code F.338
Also written as F338 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.338 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 has detected that the settings controlling its flue system do not match the physical installation, preventing it from operating safely. (As reported on Vaillant ecoTEC plus)
Pick your boiler brand for the F.338 fix
Source
Information for the F.338 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