Your boiler has lost its memory of whether it is a 24kW or 30kW model, meaning it cannot operate safely until its settings are re-programmed.

Boiler configuration fault (refer to 24 or 30 kw)

What causes this fault?

This fault occurs when the boiler's main control board loses the specific software settings that tell it which model it is currently operating. This is usually caused by a sudden electrical surge or a technical malfunction within the Printed Circuit Board's memory chip. Without this identity information, the boiler shuts down as a safety precaution because it doesn't know how much gas to burn.