Q. On Yom Tov when someone had his stove fit with a special indicating light that shows if electricity is flowing or not at that time into the element and also has the standard indicator light disconnected, can you turn off the stove when the light is off?

A. In principle it would appear that this should be permitted since the thermostat has turned off the flow of electricity into the element at that time, thus turning off completely that element would seem not be effecting any change. However, Horav Shlomo Miller Shlit”a pointed out that electricity is still flowing into the thermostat itself and when you turn off completely the controlling knob you are terminating the electrical flow into the electronic circuitry of the thermostat and that should be avoided on Yom Tov.

Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit”a