How much does it cost to fix boiler error code Flue Thermistor Fault?

Typical repair cost for the boiler Flue Thermistor Fault fault is £150-250 including labour.

Flue Thermistor Fault High

Boiler Fault Code Flue Thermistor Fault

Also written as FLUETHERMISTORFAULT — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code Flue Thermistor Fault 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 detected an issue with the sensor that monitors the temperature of the exhaust fumes leaving the unit, causing it to stop operating for safety reasons. (As reported on Keston Heat 45)

Pick your boiler brand for the Flue Thermistor Fault fix

Keston Flue Thermistor Fault 1 model

Source

Information for the Flue 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