How much does it cost to fix boiler error code CH light On?

Typical repair cost for the boiler CH light On fault is £120-250 including labour.

CH light On High

Boiler Fault Code CH light On

Also written as CHLIGHTON — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code CH light On appears across 1 boiler brand and 2 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has automatically turned itself off because the water inside it is getting too hot, likely due to a circulation problem. (As reported on Worcester Bosch 28 RSF)

Pick your boiler brand for the CH light On fix

Worcester Bosch CH light On 2 models

Source

Information for the CH light On 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