How much does it cost to fix boiler error code 373?

Typical repair cost for the boiler 373 fault is £120-250 including labour.

373 High

Boiler Fault Code 373

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code 373 appears across 3 boiler brands and 6 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 communication with an extra system component, such as an external controller or a zone management device, preventing it from functioning correctly. (As reported on ECA FELiS FL 50 HM)

Pick your boiler brand for the 373 fix

ECA 373 1 model Viessmann 373 1 model Worcester Bosch 373 4 models

Source

Information for the 373 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 7 July 2026