F25 High

Boiler Fault Code F25

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code F25 appears across 4 boiler brands and 16 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is heating up too quickly, causing it to shut down to prevent damage from overheating. (As reported on Vaillant ecoMAX Pro 28E)

Pick your boiler brand for the F25 fix

Ferroli F25 4 models Glow-worm F25 9 models Saunier Duval F25 1 model Vaillant F25 2 models

Source

Information for the F25 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