How to Replace Electric Resistors on Electric Garage Heaters

What You'll Need
Correct type of screwdriver with insulated handle
Owner's manual for the garage heater
Correct voltage resistor
Workbench or table
Rubber insulating mat
Eye protection
Nonconducting footwear

When electric garage heaters stop working it is important to ascertain the cause and fix it promptly in order to avoid fire hazards. The primary cause of heater failure is usually that a small electrical resistor has blown and needs replacing. Follow these suggestions to make this simple repair to your electric garage heater quickly and effectively.

Step 1: Disconnect the Garage Heater from the Electrical Supply

Unplug the garage heater and remove it from the mounting brackets, if it is hung up on a wall. Examine it for damage including a loose electrical cord or open access panel. Take it to your workbench to perform the repair. Put a rubber mat on top of the workbench if it is made of steel or aluminum, to prevent electrical shocks.

Step 2: Consult the Owner's Manual for Your Heater

Turn to the applicable section of your heater owner's manual. The manual will usually include a diagram that shows where the resistor is and how to remove and replace it. It will also state the correct size of voltage resistor to buy. A diagram of the resistor should also tell you its maximum heat rating, in degrees C (Celsius). A typical heat rating is 150 degrees C. Ensure when you buy the new resistor that you get one with the same maximum heat rating. Using a resistor with a higher heat rating can cause a circuit overload that may start a fire. Follow the directions in the owner's manual precisely to prevent damage to the garage heater, and avoid injury to yourself.

Step 3: Open Up the Garage Heater Access Panel

Use the correct type of screwdriver to open up the access panel, and find the resistor. It should show evidence of being blown out, such as a crack, a split aluminum bracket or discoloration.

Follow the electrical diagram to remove the resistor from the heater. Make any pulling or turning motions with care to avoid dislodging other wires or parts of the electrical circuit that operates the heater. It will be embedded in the electrical circuit at both ends. Release both connections carefully, then pull out the expended resistor.

Step 4: Insert the New Resistor

Slip the new resistor into the electrical circuit and connect it carefully at both ends according to the directions in the owner's manual. Use your hands to do this, keeping all metal tools well away from the electrical circuit.

Step 5: Test the Garage Heater for Proper Function

Put the garage heater back in its normal location, and plug it back into the electrical outlet. Turn on the power switch and check that it is working correctly once more. If the heater still does not function correctly, unplug it and remove the entire back section of the heater to check out other possible causes of malfunction. Consult the section of the owner's manual that discusses typical problems and possible solutions.