BoilerFaultCodes 042 High
Boiler Fault Code 042
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 042 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.
Most common meaning Your boiler's main control unit has detected a serious internal system error and has shut itself down as a safety precaution. (As reported on Ideal Maximiser SE)
Pick your boiler brand for the 042 fix
Source
Information for the 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 27 April 2026