Troubleshooting a Furnace Problem: Why Is My Furnace Not Turning On?

While the weather is still quite frosty, the last thing you want to discover is that your furnace is no longer working properly, or perhaps has stopped working altogether, leaving you with an uncomfortably chilly house in the morning or evening. 

It’s inconvenient and bothersome to feel discomfort in your own home, and the lack of a functioning furnace can also give rise to associated problems (the development of mold, burst water pipes, and the like) which can cause even more headaches down the line.

You need to take action the moment your furnace problem comes to your attention. While you may not have professional repair skills, the best thing you could do is to perform some simple troubleshooting so that you can figure out the issue and employ basic adjustments that can tide you over until the heating, ventilating and air conditioning or HVAC specialists arrive.

Here are the troubleshooting steps you can take:

Make sure your furnace is receiving power.

This is the number one thing you should do if it’s the first time the furnace is being switched on for the current season and it won’t respond. Try the following:

  • Check for tripped circuit breakers in the fuse box.
  • Look for the power switch at the furnace’s side and check if it is actually switched to “On” (this switch can easily be switched off accidentally because furnaces are typically found in tight spaces).
  • If the furnace has a metal housing that can be lifted, look inside. If the fuse inside it is burned and blackened, it must be replaced. However, leave the replacement to the experts since a blown fuse indicates a bigger problem in your furnace system.

Take a look for obstructions.

If your furnace has already been used in the current season, the problem could be external. The furnace’s exhaust and fresh air intake (typically found through in the attic, garage or a closet), could be blocked by boxes or damaged by insects and pets. Many of the issues we have seen are due to rodent or pet damage to wiring. Moisture issues may also be present.

Look at your thermostat settings.

Check that the thermostat is actually set to “Heat” and that the temperature is sufficient for firing up the furnace. Modern programmable furnaces can be a bit more complex for homeowners to operate, so having the user’s manual close by would be helpful in this regard.

Check the batteries.

Maybe the batteries have already died. Make it a habit to periodically check if the thermostat’s “low battery” indicator is flashing, and replace the batteries promptly.

Inspect air filters.

If the furnace works, but not in the usual heating capacity, then the air filters may be dirty. Things like hair, dust and other particles can get trapped in air filters and prevent air from flowing properly. Air filters should normally be changed every three months.

Today’s gas furnaces are designed to be more efficient, but this also means that the system can be more complicated to apply simple repair solutions to because automated components require special repair work. As such, it’s best to call in the HVAC professionals after giving your furnace the basic troubleshooting run-through so they can correctly identify and resolve the issues.

It’s also a good idea to hire an HVAC specialist to inspect your furnace or HVAC system during the winter months so that you can be all set and worry-free year round.



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1 Comment

  1. Tobias Armstrong on

    I really appreciate the troubleshooting tips you provided here. I literally just had to go through all of them to see what my furnace was doing wrong, and when they all didn't work, I called a specialist. They asked me to check all the things that you asked me to do first, so it saved a ton of time because I was able to just tell them that I had already done it all and they set me up with an appointment. Thought I'd share my thanks with you!

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