Your boiler is struggling to accurately measure the temperature of your hot water, which usually means your taps aren't getting hot enough or stay cold.

Cylinder charging or hot water temperature sensor faulty

What causes this fault?

This fault occurs when the boiler's internal computer stops receiving a reliable signal from the sensors that monitor your hot water temperature. The most common reason is that the sensor has either worn out internally or a connection in the wiring has become loose or corroded, preventing the boiler from knowing when to fire up to heat your water.