BoilerFaultCodes 402 High
Boiler Fault Code 402
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 402 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 internal computer has developed a serious electronic fault and can no longer control the heating properly. (As reported on Viessmann Vitodens 100-W B1GA)
Pick your boiler brand for the 402 fix
Source
Information for the 402 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