How much does it cost to fix boiler error code F18?

Typical repair cost for the boiler F18 fault is £120-280 including labour.

F18 Medium

Boiler Fault Code F18

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code F18 appears across 3 boiler brands and 6 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler's control panel has lost communication with the internal system, preventing you from adjusting settings or seeing the boiler's status. (As reported on Vaillant ecoMAX Pro 28E)

Pick your boiler brand for the F18 fix

Glow-worm F18 1 model Saunier Duval F18 3 models Vaillant F18 2 models

Source

Information for the F18 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