79 High

Boiler Fault Code 79

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 79 appears across 5 boiler brands and 19 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 its electrical supply and won't turn on, meaning it cannot provide any heating or hot water. (As reported on Worcester Bosch Greenstar Utility 18/25)

Pick your boiler brand for the 79 fix

Alpha 79 10 models Biasi 79 4 models Ideal 79 1 model Vokera 79 3 models Worcester Bosch 79 1 model

Source

Information for the 79 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