Common room thermostat issues include uneven or no heating at all. There are two sets of points to think about when setting. The set point is the temperature you'd like the room to be and the room temperature is the actual temperature of the room. To test the set point, simply turn the thermostat's set point temperature above the room's current temperature and it should come on. If not, and the room temperature continually falls, there's an issue with the wiring. To test the wiring, disconnect the red and black wires and apply temporary power to the yellow and green. The cooling system and fan should come on. The white wire is common.