It’s terrifying. Your gas furnace, which normally works fine, kicked on with a scary BANG or BOOM noise. It’s not only disturbing, but it can wake light sleepers up in the middle of the night.
What the heck is going on?
There are 2 common causes of this bang noise:
To know which is the problem, determine where the loud noise originates from. Stand near your furnace as it’s about to turn on and listen:
Let’s go into detail about these 2 issues.
Imagine a room full of gas and then someone decides to light a match. Big problem, right?
Well, that’s what’s happening in your furnace if the ignition of gas is delayed.
You see, this is what normally happens when your thermostat calls for heat from the furnace:
But a variety of issues can delay the combustion of that gas. So, the gas builds up in the furnace until—BOOM—it ignites, causing a mini-explosion.
This can harm the heat exchanger, which is very expensive part to replace.
Some causes of delayed ignition includes:
It’s no mystery that expanding metal ducts would cause a loud bang noise.
But what causes it?
Usually, too much static pressure in the ductwork. Static pressure is stationary pressure in a confined space (it’s just like blowing air in a balloon). In this case, there’s too much pressure pushing on your ductwork, causing it to expand and make a BANG noise.
Causes of high static pressure include:
If the noise came from your ducts, change the air filter (if it’s dirty). Also, open your supply vents and make sure they’re not blocked by furniture or curtains.
If that didn’t work, call a professional heating contractor to find the issue and fix it.
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Ragsdale Heating, Air, Plumbing & Electrical has been serving the metro Atlanta area for over 25 years.