How much does it cost to fix boiler error code Fault 03 / 20?

Typical repair cost for the boiler Fault 03 / 20 fault is £120-£250 including labour.

Fault 03 / 20 Medium

Boiler Fault Code Fault 03 / 20

Also written as FAULT0320 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Fault 03 / 20 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is having trouble communicating with the temperature thermostat built into its control panel, which means it doesn't know how warm your home is. (As reported on Worcester Bosch Greenstar CDi Compact)

Pick your boiler brand for the Fault 03 / 20 fix

Worcester Bosch Fault 03 / 20 1 model

Source

Information for the Fault 03 / 20 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