Your boiler's internal computer has developed a fault and is unable to send the correct signals to start the heating process.

Defective control panel.

What causes this fault?

This fault occurs when the boiler's internal computer brain, known as the PCB, suffers a hardware failure or a communication breakdown between its main circuits. The most common reason is electronic component wear or a power surge that has damaged the delicate circuitry required to manage the boiler's operations.