Your boiler is struggling to start up because a small internal fuse responsible for the control electronics has likely failed.

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

What causes this fault?

This occurs when the boiler's internal control board begins the ignition sequence to provide heating or hot water. It isn't a failure, but rather a status update showing that the fan is spinning and the electrodes are preparing to spark. You will typically see this for a few seconds every time the boiler starts a new cycle.