How much does it cost to fix boiler error code F40?

Typical repair cost for the boiler F40 fault is £80-150 including labour.

F40 High

Boiler Fault Code F40

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code F40 appears across 4 boiler brands and 15 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 water pressure level inside your heating system is currently too high or too low for it to operate safely. (As reported on Ferroli Atlas D)

Pick your boiler brand for the F40 fix

ECA F40 4 models Ferroli F40 7 models Johnson Starley F40 2 models Vaillant F40 2 models

Source

Information for the F40 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 31 August 2026