E78 High

Boiler Fault Code E78

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code E78 appears across 5 boiler brands and 50 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has reached its safety limit for monitoring the gas flame and cannot adjust itself correctly to heat your home. (As reported on Warmhaus Enerwa / Priwa)

Pick your boiler brand for the E78 fix

Alpha E78 18 models Baxi E78 27 models Biasi E78 3 models Potterton E78 1 model Warmhaus E78 1 model

Source

Information for the E78 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