Your boiler has detected an internal electrical problem that is preventing it from starting up safely.

Boiler electr. system fault

What causes this fault?

This fault occurs when the boiler's main control board fails its internal safety checks during the startup sequence. It is often caused by a communication error between the electrical components or a physical failure within the printed circuit board itself. In some cases, a power surge or moisture ingress can damage the delicate circuitry, leading to this total system shutdown.