Your boiler's electronic control system has detected a failed safety fuse, meaning it cannot start up or provide heating and hot water until this internal electrical component is replaced.

Please wait, initialisation in progress. 24 V fuse blown.

What causes this fault?

This code appears when the boiler is attempting to light the flame but the internal sensors haven't confirmed a successful ignition within the standard timeframe. It is often caused by a weak spark from a worn ignition electrode or a delay in the gas reaching the burner. While the boiler is trying to correct itself, it indicates that the ignition components are likely deteriorating or need cleaning.