3 Strange Sounds Coming From Your Furnace (and What They Mean)

Happy New Year 2018

Welcome to 2018. The entire team at Anchor ClimateCare wishes you a very Happy New Year.

January in central Ottawa and Embrun means freezing temperatures. It also means your furnace is working overtime to keep you warm.

As your home heating system is running, you might hear the following noises:

  • Abrasive scraping sounds.
  • Suddenly loud bangs or pops.
  • Shrill squeals and whines.

All of which are bad news.

If you hear any (or a combination) of the sounds listed above, here’s what your furnace is trying to tell you.

Abrasive scraping sound = Blower wheel issue

  • This is a very serious issue. Should you hear metal-on-metal scraping, contact us ASAP

Without a blower wheel, the warm air your furnace generates stays there.

It doesn’t circulate through your ducts; meaning it can’t reach the various rooms in your home.

Blower wheel

Usually, there are three reasons why your blower wheel isn’t working properly:

1. It broke loose from the shaft: Blower wheels are hooked up to a motor shaft via a set screw. If the screw pops loose, the wheel becomes dislodged and scrapes against the casing assembly.

2. The wheel itself is busted: Only one course of action here; replace the wheel outright.

3. Broken motor mount: Not good news. The complete unit (blower wheel, casing assembly, set screw, everything) has buckled and landed on the interior housing.

Suddenly loud bangs or pops = Burner or air duct issue

Your furnace is meant to run quietly and smoothly. It shouldn’t sound like popcorn is being made in there.

Intermittent banging and/or popping are usually indicative of one of two things:

  1. The burners are dirty

Dust, gunk and other unwanted particulates can reach the burners within the furnace. That, in turn, causes the following to happen:

  • Excessive gas builds up near the burners.
  • The burners cannot ignite properly.

That banging or popping sound you hear? That’s gas building up and igniting (which can be dangerous).

Tiny pops here and there may not seem like much.

But remember, those little bangs are actually small explosions. Over time, that’ll do some damage to your furnace (especially the heat exchanger).

Air duct

  1. Metal air duct expansion and contraction

Time for a little science 101:

  • The addition of heat causes metal to expand.
  • The removal of heat causes metal to contract.

Each time the furnace blower is turned on, heat is generated and sent through your duct work; forcing it to expand.

Turn off the blower to take away heat and the ducts contract.

As your metal ducts expand and contract (over and over again), they’ll make a banging or popping noise.

There are a few ways to remedy this:

  • Install bigger ducts which provide a better fit (the larger the duct, the less room it has to expand).
  • Open closed vents to allow heat to exit the duct and not become trapped inside.
  • Clean and/or replace a dirty air filter for more efficient air flow from your furnace into your duct system.

Shrill squeals and whines = A bunch of issues

Does your furnace sounds like it’s crying?

If so, here’s what’s going on inside:

  • The shaft bearings have dried out and need to be lubricated with oil.
  • The blower motor (mentioned earlier in this blog) is compromised in some fashion.

Hear any of these sounds? Contact us now.

  • It’s highly recommended you do not look inside your furnace should you hear any of these noises.

Your furnace is a complex system of moving parts, electrical components, and flowing gas. You could make the problem worse or injure yourself.

Here’s what to do instead:

Really worried about your furnace?