F.28 High

Boiler Fault Code F.28

Also written as F28 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed

Fault code F.28 appears across 3 boiler brands and 63 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is failing to light because it isn't receiving gas or the ignition system isn't creating a spark. (As reported on Vaillant Thermocompact)

Pick your boiler brand for the F.28 fix

Glow-worm F.28 6 models Heatline F.28 4 models Vaillant F.28 53 models

Source

Information for the F.28 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