Your boiler's main internal computer has developed a fault and is no longer communicating correctly with the rest of the system.

Defective control panel.

What causes this fault?

This fault occurs when the boiler's central control board suffers an internal electronic failure, preventing it from sending commands to the burner or pump. It is usually caused by aging components on the circuit board or a sudden electrical surge that damages the sensitive microprocessors. In some cases, loose wiring connections between the interface and the main board can also trigger this error.