How to fix an electric furnace that won’t turn on

If your electric furnace isn’t turning on, it can be frustrating, especially when you need heat the most. The good news is, you can tackle many of the common issues yourself. We’ll walk you through the most likely causes and how to fix them yourself. We’ve got you covered with expert DIY tips and troubleshooting advice so let’s get your furnace back up and running so you can stay warm all winter long!

Please note: The information provided here may not align perfectly with your specific appliance model. While we strive to offer helpful tips for a wide range of DIY appliance repairs, different models and setups may require unique troubleshooting steps, error codes, or part replacements. For the most accurate guidance, we recommend consulting the user manual for your appliance or contacting us with any questions.

Safety precautions

Safety comes first when working on any appliance. Here are some practical tips to help keep you safe:

• Always turn off the power by unplugging the appliance or switching off the circuit breaker before starting. This protects you from the risk of electric shock.
• Wear insulated gloves to protect your hands from sharp edges, pinching hazards, or debris.
• Take your time and work at a steady pace to avoid accidents or injuries.
• Make sure your workspace is well-lit so you can clearly see and access the parts you’re working on.
• Keep your area organized and free of clutter, and ensure children and pets are kept away from the workspace.
• Never handle internal parts with wet hands. Make sure both your hands and the work area are completely dry.
• Check your appliance’s user manual for specific instructions or safety guidelines related to your repair.
• Handle parts gently to prevent damaging the appliance or injuring yourself by using too much force.
• Wear safety glasses if you’re dealing with chemicals, dust, or large debris to protect your eyes.
• If the appliance was recently used, give it time to cool down before working on any heated components.
• Take photos or notes of wiring connections before disconnecting anything. This makes reassembly much easier.
• Avoid touching exposed wires or terminals. If you need to handle wires, use non-conductive tools or wear insulated gloves to reduce the risk of electrical shock.

Check the power supply

Before diving into any other possible issues, it’s important to check if your furnace is actually getting power. If the furnace isn’t receiving power, it won’t turn on, no matter how well everything else is working. What you need to do:

1. Start by checking the circuit breaker for the furnace. If it’s tripped, flip it back on.
2. If the breaker is fine, look for any blown fuses (if your furnace uses them). If a fuse is blown, you’ll need to replace it with the same type and size.
3. Make sure the furnace is plugged in properly and that there are no issues with the power cord.
4. If you’re still having issues, use a multimeter to test if there’s voltage coming through the power lines to the furnace. 
5. Set the multimeter to measure AC voltage and place the probes on the power terminals (refer to your manual to locate these). 
6. If you don’t read the correct voltage, the issue could be within the electrical supply, and you might need to call an electrician.

Inspect the thermostat

A thermostat that’s not working correctly can cause your furnace to not turn on. If the thermostat is set too low or malfunctioning, it might not be sending the proper signals to your furnace to start heating. What you need to do:

1. First, make sure the thermostat is set to the “heat” mode and the temperature is higher than the current room temperature.
2. If it’s a programmable thermostat, check if the schedule is set correctly. Sometimes it’s as simple as an incorrect program.
3. Swap out the batteries in your thermostat if you haven’t done so recently. A low battery can cause the thermostat to malfunction.
4. If your thermostat is still not working, test it with a multimeter. 
5. Set the multimeter to measure continuity, then place the probes on the thermostat terminals. When the temperature setting is reached, the thermostat should complete the circuit. 
6. If there’s no continuity when it should be, the thermostat is likely faulty and needs to be replaced.

Read more: 12 simple space heater safety tips for this winter

Examine the furnace switch

Sometimes, the furnace switch can be the culprit behind a furnace that won’t turn on. The furnace has an on/off switch, usually located near the furnace or on the wall, that must be in the “on” position for the furnace to operate. What you need to do:

1. Check the switch to ensure it is in the “on” position. If it is off, turn it on and try running the furnace again.
2. If the switch appears to be in the “on” position but the furnace still won’t start, it might be malfunctioning. Test it with a multimeter to ensure it is completing the electrical circuit properly.
3. Set your multimeter to measure continuity. Touch the multimeter probes to both terminals of the furnace switch. 
4. If the multimeter shows no continuity when the switch is on, the switch is likely faulty and needs to be replaced.

Read more: Your guide to choosing a space heater

Inspect the safety switch

The safety switch in an electric furnace ensures that the system runs safely by preventing operation in unsafe conditions. If this switch is faulty or tripped, it may prevent your furnace from turning on. What you need to do:

1. Check the location of the safety switch in your furnace. Typically, it’s near the blower or the control board.
2. Look for any signs of damage or misalignment in the safety switch.
3. If you find the switch is tripped, reset it according to the manufacturer’s instructions (usually by pressing a button or flipping a switch).
4. Use a multimeter to test the safety switch for continuity. Set the multimeter to the lowest resistance setting and place the probes on the switch’s terminals. 
5. If the switch is functioning properly, it should show continuity when closed. If there’s no continuity when the switch is supposed to be closed, you may need to replace it.

Examine the furnace control board

The control board is the brain of your furnace, managing and directing all electrical signals to various parts of the system. If there’s an issue with the control board, it can prevent the furnace from turning on. What you need to do:

1. Inspect the control board for any visible signs of damage such as burnt areas, scorch marks, or loose connections.
2. If you see any signs of damage, the control board may need to be replaced.
3. Test the control board using a multimeter. Set the multimeter to continuity mode and test the connections from the control board to other furnace components like the fan, igniter, and transformer. 
4. If you’re not getting continuity where you should, the control board may be malfunctioning.
5. If the control board is malfunctioning, you’ll need to replace it with a compatible part based on your furnace’s model number. 

Read more: 12 things you should know about portable space heaters

Additional information

Thanks for reading! If you need replacement parts, grab your model number and head to AppliancePartsPros.com. We offer over two million parts and most orders arrive in two business days. If you need help finding the right part or placing an order, you can contact our team at 1 (877) 477-7278.

While you’re waiting for your new part to arrive, you can explore our DIY blog and watch thousands of video tutorials on our YouTube channel.

Be sure to follow us on Facebook, Twitter and Instagram to see our latest repair guides!