Your boiler has detected a communication error between its internal sensors and the main control board, preventing it from heating your home safely.

Electronics/sensor fault; Short-circuit in flow or return sensor or electronics defective

What causes this fault?

This fault occurs when the boiler's main computer receives conflicting or impossible signals from its internal temperature sensors. It is usually caused by a short circuit in the wiring or a hardware failure within the control board itself, which prevents the system from accurately monitoring the water temperature. Because the boiler cannot guarantee it is operating at a safe heat level, it shuts down as a safety precaution.