Your boiler's main internal computer has developed a malfunction and is no longer able to control the heating process safely.

There is an internal fault in the Automatic Control Module.

What causes this fault?

This fault occurs when the boiler's main control board experiences an internal electronic failure or a breakdown in communication with other components. The most common reason is age-related wear on the circuit board's microprocessors or a sudden electrical surge that has damaged the delicate internal components.