How much does it cost to fix boiler error code 342?

Typical repair cost for the boiler 342 fault is £150-300 including labour.

342 High

Boiler Fault Code 342

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 342 appears across 1 boiler brand and 5 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is heating the water much faster than it is able to move it away, causing the system to stop as a safety precaution to prevent overheating. (As reported on Worcester Bosch Greenstar 27CDi)

Pick your boiler brand for the 342 fix

Worcester Bosch 342 5 models

Source

Information for the 342 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