The wheel may have become loose and is making the noise by hitting the blower casing.
Furnace blower wheel noise.
The motor itself can also become out of balance.
Sometimes a broken blower wheel can also be the source of this distinct noise.
A broken blower wheel will vibrate in its housing resulting in squealing scratching and banging sounds.
Shut your furnace off if you have a compromised mount.
Most likely the blower fan has become loose and is creating the sound by hitting against the blower house casing.
The blower wheel is broken and needs replacing.
Have a pro take a look to avoid further damage to your furnace.
Blower wheel loud clanking or scraping classified as a metal against metal sound signals a serious problem with the furnace s blower wheel.
The cause of this noise is usually a problem the furnace s squirrel cage blower wheel.
Thumping and vibrating sounds are the results of an unbalanced blower wheel.
Get a professional to tighten the wheel.
Blower wheel is loose from the motor wheel.
Here are some of the reasons your furnace could be making a funny noise.
A broken motor mount causes the blower wheel to drop and rattle against the housing.
When your furnace blower wheel is broken it will make your furnace sound like metal scraping against metal and will really hurt your ears.
If you hear this sound turn off your furnace immediately.
If you hear this noise turn off your furnace immediately to prevent any further damage to the furnace.
The blower wheel can be making the scraping noise for different reasons.