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

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

I High

Boiler Fault Code I

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code I appears across 4 boiler brands and 9 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is not heating the water up enough because it is either not getting enough gas or a vital internal part is stuck. (As reported on Worcester Bosch 24i / 28i Junior)

Pick your boiler brand for the I fix

Ariston I 1 model Baxi I 5 models Main I 1 model Worcester Bosch I 2 models

Source

Information for the I 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 31 August 2026