Furnace Troubleshooting Guide – And When to Call a Specialist

It’s always frustrating when your furnace won’t turn on or is acting strangely in some way. Malfunctions never seem to happen at the right time. But not every problem needs an HVAC repair specialist to fix. Here are a few things to try before you call an HVAC service to come and take a look at the problem.

Check the Filter

Your HVAC filter helps keep your home’s air clean and healthy by catching dust and other debris passing through it. However, that means they get dirty over time. When excessive dirt and dust clog it up, that can impede airflow. If it goes on long enough, it can even stop your HVAC system from turning on. In extreme cases, an overdue filter change can become a fire hazard and even shorten the life of your entire HVAC system.

That’s why we recommend changing the air filter on a regular basis. But of course, life happens and sometimes maintenance like that falls by the wayside. If your HVAC system is behaving strangely, start with the filter. Your system should have instructions to change it. Follow them carefully.

Check Your Thermostat

Your thermostat is responsible for a lot of your furnace’s proper functioning. Make sure its batteries are fresh and switch them out for new ones if necessary.

Try adjusting the temperature, even if your home feels comfortable where it is. Sometimes a quick adjustment can cause the whole system to kick back in. Then you can adjust the thermostat back to the temperature you want it at.

If you have an electromechanical thermostat, you might need to open it up and dust the internal mechanisms. Use a soft cloth, clean paintbrush, or paper towel – something that won’t leave lint or residue behind. Be gentle so you don’t break any inner workings.

Next, make sure your thermostat isn’t getting false readings from sources other than the house’s ambient temperature. Anything near the thermostat that gives off heat could be doing this – harsh sunlight, a hot lamp, your oven, space heaters, etc. Move them or turn them off if you need to.

Check the Date and Time

If your system works on a timer and the time and date settings are wrong, it stands to reason that your HVAC system won’t give the temperature output you want. Double-check this and make adjustments if you need to.

Turn Off the Breaker

Then check the fuse for the furnace. Be sure to leave the breaker off for a few minutes. After switching it back on, wait for at least 15 minutes for the whole system to reset. It takes a little while to get everything back up and running after being shut off, so don’t panic if you don’t see any results right away.

Check Your Furnace Flame

If you have a gas furnace, the color of your furnace’s flame shows that fuel is burning safely and efficiently. The flame should always be blue, perhaps with a yellow tinge at the tip. If it’s any other color – red, yellow, purple, green, anything – contact a professional right away.

There’s a never-ending list of things that could potentially be wrong with your HVAC system. If a few troubleshooting methods don’t work, it’s generally best to just call a professional for help just to be safe.

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