Why does the Genius Radiator Valve turn off when a window/door is opened?

The Genius Radiator Valve features an 'open-window' function, which closes the valve if the room temperature is falling dramatically, thus reducing the wasted heat if the app is set to heat a room but a window is then opened.

The heat is turned off to the valve for up to 30 minutes before the valve returns to its original settings. When open-window has been activated, the function is then left for 45 minutes before it can be activated again.

Pressing any buttons on the valve does not affect the open window function and the only way to clear this is to remove the batteries from the valve and put them back in after 10 seconds.

Be aware that the open-window function will be affected, if curtains or furniture is covering the valve thus preventing it from detecting the decreasing temperature. The open-window feature is activated with a temperature decrease of approx. 0.5 °C over 3 min.

It is not possible to disable this feature on the valve.