BoilerFaultCodes FLOW/RETURN THERMISTOR FAULT High
Boiler Fault Code FLOW/RETURN THERMISTOR FAULT
Also written as FLOWRETURNTHERMISTORFAULT — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code FLOW/RETURN THERMISTOR FAULT 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 lost the ability to accurately measure the temperature of the water circulating inside it, so it has purposefully shut down to prevent damage. (As reported on Ideal Vogue System)
Pick your boiler brand for the FLOW/RETURN THERMISTOR FAULT fix
Source
Information for the FLOW/RETURN THERMISTOR FAULT 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 7 July 2026