How much does it cost to fix boiler error code 003?

Typical repair cost for the boiler 003 fault is £120-250 including labour.

003 High

Boiler Fault Code 003

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code 003 appears across 1 boiler brand 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 failed to ignite the flame correctly after several attempts and has stopped working to prevent a buildup of gas. (As reported on Navien NCB)

Pick your boiler brand for the 003 fix

Navien 003 6 models

Source

Information for the 003 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