Your boiler's main control computer has developed an internal electrical fault and can no longer safely operate the system.

There is an internal fault in the Automatic Control Module.

What causes this fault?

This fault occurs when the boiler's internal computer suffers a hardware failure, meaning it can no longer process data or send signals to other components safely. The most common reason is typical wear and tear on the electrical circuitry or a sudden power surge that has damaged the delicate components on the control board.