Your boiler's internal control board cannot safely communicate with the gas valve, preventing the system from igniting for your heating and hot water.

Gas valve relay faulty

What causes this fault?

This fault occurs when the boiler's main control board detects a hardware failure in the electrical relay that manages the fuel supply. It means the system can no longer safely open or close the gas valve, so it shuts down as a protective measure to ensure gas cannot flow uncontrollably. The root cause is typically a component failure on the printed circuit board itself or a communication breakdown between the board and the gas valve.