The limit switch is a very important safety device on a furnace. The function of a limit switch is to protect the furnace from overheating. These switches come in a variety of temperature ratings and are located at critical locations above the heat chamber on the various models of furnaces. Therefore, it is very important that when one of these switches is replaced, you do so with the properly rated switch.
8516-II, 8520-II, 8525-II, 8531-II, 8535-II, 8935-DC-I, 8535-AC-I, 8940-DC-I and 8940-AC-I.