How much does it cost to fix boiler error code 78?

Typical repair cost for the boiler 78 fault is £100-280 including labour.

78 High

Boiler Fault Code 78

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 78 appears across 6 boiler brands and 23 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected a temporary internal communication error or a sensor synchronization issue that is preventing it from running properly. (As reported on Vokera Linea HE)

Pick your boiler brand for the 78 fix

Alpha 78 10 models Atag 78 4 models Biasi 78 4 models Ideal 78 1 model Vokera 78 3 models Worcester Bosch 78 1 model

Source

Information for the 78 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