25 High

Boiler Fault Code 25

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code 25 appears across 13 boiler brands and 78 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 that a temperature sensor is not working correctly, which has caused the system to stop running to prevent overheating. (As reported on Potterton Performa System HE)

Pick your boiler brand for the 25 fix

Alpha 25 19 models Baxi 25 7 models Biasi 25 4 models Chaffoteaux 25 4 models Ferroli 25 3 models Glow-worm 25 1 model Ideal 25 4 models Johnson Starley 25 10 models Main 25 3 models Potterton 25 5 models Remeha 25 2 models Viessmann 25 12 models Vokera 25 4 models

Source

Information for the 25 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