Your boiler has detected a problem with the sensor that monitors hot water temperature, which may result in no hot water or inconsistent temperatures.

DHW thermistor fault

What causes this fault?

This fault occurs when the sensor responsible for measuring the temperature of your tap water fails to send a consistent signal to the boiler’s control board. The most common reason is that the sensor has physically degraded over time or developed an internal electrical short, preventing the boiler from knowing how hot the water is. In some cases, it can also be triggered by loose or corroded wiring connections between the sensor and the main computer.