BoilerFaultCodes F.042 High
Boiler Fault Code F.042
Also written as F042 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code F.042 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 lost the electrical connection to the part that manages the gas supply, meaning it cannot safely start up and will stop providing heat and hot water. (As reported on Vaillant ecoTEC Plus 836)
Pick your boiler brand for the F.042 fix
Source
Information for the F.042 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