How much does it cost to fix boiler error code F.03?

Typical repair cost for the boiler F.03 fault is £90-180 including labour.

F.03 Medium

Boiler Fault Code F.03

Also written as F03 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code F.03 appears across 3 boiler brands and 11 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's hot water cylinder sensor is not responding properly, which means the system cannot correctly measure the temperature of your stored hot water. (As reported on Glow-worm Energy 35 Store)

Pick your boiler brand for the F.03 fix

Glow-worm F.03 1 model Ideal F.03 9 models Vaillant F.03 1 model

Source

Information for the F.03 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