Furnace makes bang sound when shuts off

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by LL in Toronto about 2 years ago

Hi, I was wondering if anyone knows why my furnace makes a bang sound when it shuts off. It doesn’t happen everytime it shuts off. The bang actually sounds like the sheet of metal on the furnace is pushing in or out. I think it may be called ‘oil canning’. What can I do to stop it from doing that ? Other than that, the furnace seems to be working fine.


4 Responses


by Aaron from Kroll Corp. about 2 years ago

It might be due to the pressure change when fan stops blowing. The decrease in pressure when the fan stops may be causing a piece of sheet metal to bend back in, causing the bang. Just a thought!


by jodi from douro about 2 years ago

could it be the airducts banging ?

Ours do, and creak and groan..


by D. Watters in Oakville about 2 years ago

I had that happening a few years ago. When I had enbridge come to look at it, they locked it down and I had to replace furnace…..worth getting someone out there to look at it..


by Pacific Home Comfort Experts about 2 years ago

If it is only making that sound on the blower shut down, it is most likely your return ducts letting go after it has been sucked in when the blower came on. The ducts can be strapped or you may not have enough return air.

Pacific Home Comfort Experts
905-202-3225 or 416-889-7529

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