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

Typical repair cost for the boiler C fault is £150-350 including labour.

C High

Boiler Fault Code C

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code C appears across 6 boiler brands and 16 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 detect a flame or has registered a new control component, meaning it has temporarily locked out for safety and stopped providing heating and hot water. (As reported on Halstead Ace HE)

Pick your boiler brand for the C fix

Ariston C 1 model Baxi C 5 models Halstead C 2 models Main C 2 models Pro C 3 models Worcester Bosch C 3 models

Source

Information for the C 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