Your boiler is struggling to accurately detect the temperature of your hot water supply, so it has safely shut down to prevent overheating.

Hot Water NTC Fault

What causes this fault?

This fault occurs when the sensor responsible for monitoring the temperature of your hot water fails to send a reliable signal back to the main control board. The most common reason is that the internal component of the sensor has degraded over time or developed an electrical short, preventing it from reading the water temperature accurately. In some cases, it can also be triggered by a loose or damaged connection in the wiring leading to the sensor.