Your boiler's internal computer has encountered a communication error or a serious hardware failure that prevents it from running safely.

Electronic fault | Electronics defect

What causes this fault?

This fault occurs when the boiler's main control board loses the ability to properly communicate with the gas valve. The most common reason is a physical failure of the internal circuitry on the printed circuit board or a short circuit in the wiring connecting these two vital components. Because the computer can no longer safely control the flow of gas, it shuts the system down as a safety precaution.