Your boiler has detected an internal electrical communication error, meaning it cannot properly coordinate its functions to provide heat and hot water.

Boiler electr. system fault

What causes this fault?

This fault occurs when the boiler's internal computer parts stop talking to each other, similar to a crash on a home PC. It is usually caused by a hardware failure on the main circuit board or a loose connection in the internal wiring that prevents the boiler from sending safety signals. Because the system can no longer double-check its own safety sensors, it shuts down immediately to prevent any damage.