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

Typical repair cost for the boiler I.003 fault is £90-140 including labour.

I.003 Low

Boiler Fault Code I.003

Also written as I003 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code I.003 appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has reached its programmed service interval and is kindly reminding you that it is time for its annual health check. (As reported on Vaillant ecoTEC plus)

Pick your boiler brand for the I.003 fix

Vaillant I.003 3 models

Source

Information for the I.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