An AC thermostat, or air conditioning thermostat, is a type of thermostat that controls the air in the house or building. The AC thermostat works by turning on or off the AC unit depending on the temperature in the building. You will set the thermostat at a certain temperature, and when the house cools to that temperature, the unit will turn off.
how To Check :
difficult to check in summer,, but one method : set your thermostat at Low point.. and turn on the A/c ..