Your boiler has detected that the hot water is getting too hot, likely due to a sensor measurement issue or a temporary building of heat in the system.

DHW actual temperature: Actual hot water temperature.

What causes this fault?

This fault occurs when the boiler detects that the water coming out of your hot taps is reaching an unsafe or unexpectedly high temperature. The most common reason is a faulty temperature sensor (NTC) providing an incorrect reading to the control board, or a small blockage in the heat exchanger that prevents heat from being transferred efficiently.