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No Heat? Learn Basic Furnace Troubleshooting Tips

Did your furnace give out? It’s understandable given all of the overtime work it’s been putting in. But before assuming the worst and calling in a professional, learn some basic furnace troubleshooting tips to get your heat running again.

Furnace Troubleshooting Tips

Although we hope that these troubleshooting tips help you get the heat back on, it is extremely important to schedule annual heating and cooling maintenance to prevent breakdowns and ensure your warranty remains in effect. A maintenance plan is recommended to save money and extend the life of your heating and cooling system.

Without further ado,

5 Furnace Troubleshooting Tips

  1. Breaker Box – Check to see if your furnace threw the breaker switch. If you don’t have your breaker panel labeled, now is a good time to do so. After locating the correct breaker switch, simply flip the switch all the way to the “off” position (opposite direction of all the other switches) and then flip it back on (same direction as all the other switches).
  2. Furnace Filter – If your power is on, you should check your furnace’s air filter. Sometimes, your furnace will actually shut itself off if the filter is dirty and clogged enough. This is done as a precautionary measure since an overloaded heat exchanger can be dangerous and lead to costly repairs.
    • If you don’t remember the last time you replaced the filter, then it is probably due for one. To make sure that you remember to check and/or change the furnace filter every 30-90 days, you should set a reminder on your phone or calendar for the first of every month to check the filter.
  3. Blower Panel – Like with the furnace filter, sometimes a furnace won’t turn on as a precautionary measure if the blower panel is ajar. This prevents the blower from turning on while someone is working on the furnace. If your furnace won’t start, make sure the door that houses your blower motor is fully closed.
  4. Thermostat – The next thing you want to check is your thermostat. Make sure that it is set to “heat” and that the thermostat is set above the room temperature. Also, check to see if you need to change the batteries. Here is a good video for learning how to change your thermostat’s batteries if you have never done so before:
  5. Gas Valve & Pilot Light – If the previous steps did not solve your problem, the issue may be with your gas valve or pilot light. The gas valve may have inadvertently been closed or forgotten to be turned back on when someone was working on the furnace. If the gas valve, your furnace won’t have the fuel necessary to run.
    • To locate your gas valve, trace the gas line to your furnace until you see a handle on the pipe. If the handle is perpendicular, turn it until it is parallel with the pipe. Sometimes there will be a separate gas valve located on or around your furnace. Look around to ensure the gas is “on.”
    • Furnace Troubleshooting
    • If you have an older furnace, you should check the pilot light to see if it is lit. If the gas is on, but still no flame, you will want to turn the gas “off” again in order to relight the pilot light. Once the gas is off and all the fumes have disappeared, now it is safe to light the pilot light. Make sure you double check your model’s specific manufacturer instructions, but it is safe to say that you either have an ignitor button or will have to manually light it with a long match or lighter. For most furnaces, this how-to video should do the trick:

Hopefully, these 5 Furnace Troubleshooting Tips were able to solve your heating problem. If not, don’t hesitate to call the HVAC professionals at Larry & Sons.

For furnace installation, repair, & maintenance, Larry & Sons is your trusted heating and cooling service provider in the tri-state area, including Hagerstown, Frederick, and Middletown.

We understand the importance of keeping warm, especially with the weather being as it is. We’ll repair your furnace in a timely manner so that you can get back to enjoying a warm and comfortable home.


If you haven’t already, don’t forget to schedule your annual heating and cooling tune-up! 301-733-5428

With our maintenance plan, we’ll remind you of your annual tune-up, provide 15 % off all repairs, and much more!

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