Boiler Fault Code DHW Thermistor Fault

Also written as DHWTHERMISTORFAULT — same fault.

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

Fault code DHW Thermistor Fault 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 is struggling to accurately measure the temperature of your hot water, which typically means your taps will only run cold or have inconsistent heat. (As reported on Ideal Logic Code Combi ESP1)