4 Common Reasons Behind a Malfunctioning Furnace

During one cold winter evening, when you and your loved ones are staying home and feeling grateful for your heating system, all of a sudden, your furnace decides to stop working. The situation can be every homeowner’s worst nightmare, especially since the temperature outside is dropping by the minute and you have no idea how to tinker with a faulty furnace.

Typical reasons that can cause a broken furnace include a buildup of dust and dirt particles lodged on its air filter or air ducts, lack of maintenance, gas line problems, and a worn-out unit. It’s crucial to get a furnace checkup even before the cold season arrives to ensure you’ll have adequate heating when you need it the most.

If you want to avoid facing a broken unit heater, mostly during the dead of winter, it’s crucial to know the cause behind it, so you can either fix it yourself or call an expert for help. Keep reading to find out the common reasons your furnace is malfunctioning and how to solve them.

Reasons Your Furnace Isn’t Working

Your furnace can stop working out of nowhere due to several reasons. But if you tend to it and seek to find the cause immediately, you can still control the situation and save your heating system from breaking down completely. You can try fixing your furnace on your own by reading the troubleshooting tips below. 

1. It Could Be a Wrong Temperature

When your furnace stops working, it’s important to remain calm and begin by checking on your unit right away because it could be your thermostat set at the wrong temperature. It should be on heating mode with a warmth that’s a few degrees higher than your room temperature. 

2. It Could Be a Faulty Circuit

After fiddling with the thermostat and nothing changes and your furnace is still not operating, you can proceed to your circuit breaker to check for any faults that may be affecting your unit. Circuit breakers are prone to either experience a short circuit or an overload, causing it to blow up. You can try flipping the switch on or having it replaced after an unrepairable fuse.

3. It Could Be a Lack of Power

If calling for furnace repairs due to a damaged fuse still doesn’t solve your problems, it could be your system’s pilot light. It may have gone out without you noticing and is usually caused by clogging, or your gas may have run out. If you light your pilot flame and nothing happens, it’s essential to call a professional to take care of the situation.  

4. It Could Be a Short Cycle

A short cycle happens when your furnace keeps turning on and off by itself, which can lead to a major problem if left unattended. The situation usually occurs because of a dirty air filter or a broken thermostat. In some cases, it can also happen because your thermostat is positioned near your heating unit. 

When a short cycle occurs, you can replace your filter or thermostat, and if none of that works, it’s better to leave the situation in the hands of a furnace professional to assess your unit. They can either suggest to repair it or get a furnace replacement.


A malfunctioning HVAC system can be quite stressful to repair, especially if you have no clue what you’re doing. The moment you experience a faulty heating unit, remember to check your thermostat, circuit breaker, and air filters. If none of them work, it may be time to ask the assistance of a professional.

Are you looking for furnace cleaning services in Calgary and Edmonton to help maintain your heating system? Legacy Heating offers solutions catering to HVAC systems, including installation and replacement of furnaces, air conditioners, thermostats, unit heaters, and more. We also provide HVAC products to cater to your needs. Get in touch with us today to get a free quote!

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