My heating unit comes on but will not stay on past 70 degrees and don't blow as hot as it usually do. Also if I set it to 80 degrees it still cuts off at 70 degrees. No matter what I set the thermostat at, 70 degrees is max.. At that point the unit shuts off. Once the house gets cool I have to cut the thermostat off and then cut it back on. It will not automatically come back like it normally due. I have a bungalow and the thermostat don't have a name on it for me to provide you with. It's a very old model, its square and you set it at the top by sliding the little slider and at the bottom it gives you the temperature of the house. I don't have a air unit attached and there's no connection on the thermostat for one. I have a York 90 plus furnace.