BoilerFaultCodes Faulty CH thermistor High
Boiler Fault Code Faulty CH thermistor
Also written as FAULTYCHTHERMISTOR — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code Faulty CH thermistor 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's internal thermometer is broken, meaning it cannot accurately tell how hot the water is and has stopped working as a safety precaution. (As reported on Glow-worm Swift Flow 100)
Pick your boiler brand for the Faulty CH thermistor fix
Source
Information for the Faulty CH thermistor 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