Your boiler is struggling to accurately measure the temperature of the water going to your taps, which might result in the water being too hot or too cold.

What causes this fault?

This fault occurs when the boiler's internal computer receives an unconventional or missing signal from the sensor that monitors your tap water temperature. The most common reason is that the sensor has either developed a physical fault or has been affected by a small amount of corrosion on its electrical connections. In some cases, localized limescale buildup around the sensor can also cause it to send inaccurate readings.