How much does it cost to fix boiler error code 42?

Typical repair cost for the boiler 42 fault is £350-£550 including labour.

42 High

Boiler Fault Code 42

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 42 appears across 8 boiler brands and 25 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's internal computer brain has experienced a critical error and can no longer control the heating system safely. (As reported on Remeha Quinta 30)

Pick your boiler brand for the 42 fix

Biasi 42 4 models Ferroli 42 3 models Grant 42 1 model Halstead 42 8 models Ideal 42 2 models Remeha 42 2 models Saunier Duval 42 2 models Vokera 42 3 models

Source

Information for the 42 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