How to Fix a Furnace: A Guide for Homeowners

Mature man examining an outflow air vent grid and duct to see if it needs cleaning. One guy looking into a home air duct to see how clean and healthy it is.

Did you know that 47 percent of American households rely on natural gas-fueled central heating systems? Meanwhile, 37 percent use electricity to power their furnace.

No matter which you use at home, you trust your furnace to keep you warm and toasty throughout the winter. But, of course, sometimes furnaces break or need minor repairs after years of use.

Thankfully, making necessary repairs doesn’t always require the help of a professional, especially if it’s something minor. We’ll show you how to fix a furnace using these troubleshooting steps in this post. So, keep reading if you want to save money and learn how to do basic DIY furnace repairs!

Check the Thermostat, Breakers, and Shutoff Switches

Before you get to work, you’ll want to ensure that your thermostat is working and switched to the proper settings. So, check that it is changed to heat rather than cool and at a warmer temperature than the room. And, if your thermostat kicks on at a certain time, you’ll want to see that the clock is correct.

If your thermostat seems to be functioning properly, check the furnace switch, circuit breakers, and fuse so you can verify that they are all on.

Change Filters

If your furnace clogs with dirt and dust, it will likely shut off or have restricted airflow. When the problem is severe, it can cause the heat exchanger to overheat and shut off before your house gets warm.

So, change your filter if your blower is running but your house isn’t getting warm. Of course, you’ll want to replace it every few months to prevent this issue from occurring again, lengthen your furnace’s lifespan, and increase its efficiency.

Flush out Drain Lines

Some furnaces drain several gallons of water a day. So, if mold or sediment blocks the drain lines, the furnace will likely shut off.

To fix this issue, remove the hose and fill it with a mixture of bleach water. Then, after a few minutes, flush it with water.

Inspect Ducts for Blockages or Leaks

Sometimes the furnace appears to work fine, but one or two rooms aren’t heating. If the registers are open, you should examine accessible ductwork and look for any places that air may leak.

You can seal gaps with metal duct tape, but avoid using the regular type since it deteriorates quickly. Of course, the best way to remedy leaks is by calling furnace repair services and contractors who have the right equipment.

Clear Debris from Vents or Heat Pumps

Does your furnace vent out the side of the house? If so, you’ll want to make sure nothing is blocking the exhaust or intake.

And, if you have a heat pump, you’ll need to remove grass and leaves from around the compressor unit.

Now You Know How to Fix a Furnace!

After reading this basic furnace repair guide, you should know how to fix a furnace that’s experiencing minor problems. Of course, if you still can’t seem to figure out what’s wrong after learning how to repair a furnace, there’s no shame in calling a professional whose expertise goes beyond common furnace problems and includes furnace replacement. But, in the meantime, fetch your toolbox and get to work!

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