How much does it cost to fix boiler error code F23?

Typical repair cost for the boiler F23 fault is £150-350 including labour.

F23 High

Boiler Fault Code F23

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code F23 appears across 3 boiler brands and 20 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has stopped working because the water isn't moving through the system correctly, which is often caused by air bubbles or a blockage. (As reported on Glow-worm Xtramax HE)

Pick your boiler brand for the F23 fix

Glow-worm F23 10 models Heatline F23 8 models Saunier Duval F23 2 models

Source

Information for the F23 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