-Your Gas Furnace Makes Noise
All furnaces make noise. There is the noise of the gas burner, the noise of the motor starting, the noise of the air circulating and the noise of the duct-work cooling after the heat stops. However, if you furnace is making a lot of noise, there might be something wrong.
While the furnace is running, listen to the noises you hear and try to pin-point where they are coming from. If the noises are in the burner, call a furnace technician right away.
1. Noise in the blower(fan) box.
Junk in the fan box -
Stop the furnace and open the fan box. Sometimes little things (like children’s toys) will get into the recirculation system and get pulled into the fan box. Then those items can bounce around inside the blower when it is spinning making a terrible racket. This rarely happens, and if it does, there is usually a hole in your filters large enough for the object to get into the fan. You are going to need to replace your filters after you remove whatever is inside the fan.
Nothing obvious – but lots of noise-
You may have a damaged fan blower cage. If the cage does not spin easily or wobbles when you spin it, you may need to replace the fan. Get a furnace technician to check this out for you.
2. Loose or broken fan belts.
Loose belts-
Loose belts can cause squealing noises when the fan first starts. You may also detect a burning rubber smell if your fan belts are loose. If you have heard either the squealing noise or smelled the burning rubber, you should replace your fan belts right away and set them to the correct tension.
Note – a damaged or jammed fan blower cage can cause the belts to squeal when the motor first starts. Check out your fan blower cage to be sure nothing is jammed into the track or rubbing (worn bearings).
Broken fan belts-
Sometimes a fan belt will start to come apart but not break all the way. These belts flap around against the housing of the blower and fan boxes making a lot of noise. Turn off the fan and remove the damaged fan belt. Replace it right away. Check for other damage that the broken belts may have caused (damage to wires, filters, duct-work and housings are common).
