Boiler Fault Code CH light On (flashing)

Also written as CHLIGHTONFLASHING — same fault.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026

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

Most common meaning Your boiler has temporarily stopped itself because it detected that the water inside is getting too hot, but it will attempt to restart automatically after a short cooling period. (As reported on Worcester Bosch 24CDi BF)