BoilerFaultCodes 25 High
Boiler Fault Code 25
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 25 appears across 19 boiler brands and 85 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 16 models Baxi 25 8 models Biasi 25 4 models Chaffoteaux 25 3 models Ferroli 25 4 models Firebird 25 1 model Gledhill 25 1 model Glow-worm 25 1 model Heatline 25 3 models Ideal 25 7 models Johnson Starley 25 5 models Main 25 5 models Potterton 25 7 models Remeha 25 2 models Sime 25 2 models Unical 25 2 models Viessmann 25 7 models Vokera 25 6 models Worcester Bosch 25 1 model
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 7 July 2026