How to Repair a Shorted Electric Heat Thermostat

What You'll Need
Replacement electric heat thermostat
Replacement electric heat thermostat battery
Compressed air
Soft brush
Torpedo level

Electric heat thermostat on your furnace will need to be repaired or replaced if it is experiencing a short. For this do-it-yourself task you need to be able to troubleshooting the exact problem to apply the proper fix. The troubleshooting process is identified below in the steps to this how-to article.

You should be comfortable working with electricity when engaging in this type of repair. If you are not comfortable working with electricity, you should give strong consideration to hiring an electrician or other qualified technician to conduct this repair for you so that you do not do any damage to your heating system that will require further expense. 

A basic understanding of how an electric thermostat works is in order. The thermostat is found in most homes as a wall-mounted thermostat. It is typically powered by a 120-volt circuit wired to a transformer to reduce the voltage. Depending on the furnace that you have this reduction in voltage can be between 12 to 24 volts. The wires are attached to your thermostat are thin.

Step 1: Addressing No Heat From Furnace

No heat in your furnace can be caused by a variety of potential causes including a tripped breaker, loose connection, bad battery (in a digital thermostat) or a thermostat that is dirty. Any of these problems can cause the thermostat to work improperly and thus the furnace not to deliver heat to your home.

You will need to check behind the electrical panel and check the circuit breakers for the furnace. If the breaker is in the off position, it has been tripped and can be fixed by simply turning it on. If this does not solve your problem, you need to remove the thermostat cover to check the battery as well as the wires. A dead digital thermostat battery can be replaced and loose or broken wires should be reset or replaced in order to return the thermostat to its working order. Use a can of compressed air to clean out the thermostat along with a sift brush to remove the dirt that may have accumulated. 

Step 2: Dealing with Heat not at the Programmed Level

If the thermostat is not delivering heat at the level in which it is programmed it may have been improperly installed. Place a torpedo level on top of the thermostat to determine the proper level and using a screwdriver, take the thermostat off of the wall and reinstall it.

Step 3: Fixing the Furnace Turning On and Off

The problem with the furnace cutting on and off rapidly is due to a dirty thermostat. This problem can be fixed by following the processing Step 1 for cleaning the thermostat wires using compressed air and a soft brush.