How much does it cost to fix boiler error code F.003?

Typical repair cost for the boiler F.003 fault is £120-220 including labour.

F.003 Medium

Boiler Fault Code F.003

Also written as F003 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code F.003 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 is having trouble communicating with the temperature sensor in your hot water tank, which means it may struggle to heat your water properly. (As reported on Vaillant ecoTEC Plus 836)

Pick your boiler brand for the F.003 fix

Vaillant F.003 3 models

Source

Information for the F.003 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