Your boiler's temperature sensor for the heating system has stopped communicating correctly, meaning your boiler doesn't know how hot the water is and will likely stop running for safety.

Central Heating NTC Fault

What causes this fault?

This fault occurs when the internal sensor responsible for measuring the temperature of the water in your radiators becomes damaged or develops an electrical glitch. The most common reason is that the sensor has physically degraded or developed a short circuit, preventing it from sending a reliable reading to the boiler’s control board.