Your boiler has stopped working because one of its internal temperature sensors has developed an electrical fault and is reporting incorrect information.

Outlet probe short-circuited

What causes this fault?

This fault occurs when the electrical sensor that measures the water temperature exiting the boiler fails or loses its connection. Over time, heat exposure or moisture can cause the sensor's internal wiring to break down or short-circuit, preventing the boiler from knowing if it is safe to continue heating.