How much does it cost to fix boiler error code F.025?

Typical repair cost for the boiler F.025 fault is £150-300 including labour.

F.025 High

Boiler Fault Code F.025

Also written as F025 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code F.025 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 that the exhaust gases are getting much hotter than they should be, or there is an issue with the electrical connection monitoring these temperatures. (As reported on Vaillant ecoTEC Plus 836)

Pick your boiler brand for the F.025 fix

Vaillant F.025 3 models

Source

Information for the F.025 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