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

Typical repair cost for the boiler Return Thermistor fault is £90-160 including labour.

Return Thermistor High

Boiler Fault Code Return Thermistor

Also written as RETURNTHERMISTOR — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code Return Thermistor appears across 1 boiler brand and 3 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 water returning to the unit, causing it to stop running as a safety precaution. (As reported on Baxi Combi Elite)

Pick your boiler brand for the Return Thermistor fix

Baxi Return Thermistor 3 models

Source

Information for the Return 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