Rattling noise coming from furnace blower

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ilyaz

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We have a Trane furnace that's about 10 years old. Lately I started hearing metal rattling noise coming from the furnace (I think from the blower) at the beginning and end of each cycle. Does this require immediate attention? Is this a serious problem with the blower likely to fail within days? Thanks
 
It's anyone's guess what's wrong with it, need to get it looked at ASAP.
Dirty and out of balance, bad bearing, weight fell off, if it's belt driven could be a bad belt.
 
If it's worse at the beginning and end of its cycle, it suggests, perhaps, loose mounting bolts or something similar might be the cause. In any event, I would say it requires immediate attention.
 
If it is a "direct drive" (no belt) my first thought is that the set screw that holds the "squirrel cage" to the motor shaft is loose, the fan turning on the motor shaft a second as it starts and spinning after the motor stops.
 
Check the fins on the blower wheel. I had a Trane unit just let go of all the fins on the wheel and scattered them everywhere. Obviously, put the wheel out of balance and caused all kinds of racket.
 
If the blower wheel is spinning on the motor shaft then it can cause severe damage to the motor.

Sometimes the fins on the blower wheel come loose and have similar sounds.

Could be debris fell into the blower wheel and is bouncing around.

Could be a host of anything else. Throwing parts at it is an expensive way to troubleshoot. You may get lucky though, it’s your call.

Personally I would get someone to look at it soon. The longer you wait the worse it will probably get.
 
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