Amana Air Command Blower Vibrates


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Old 02-14-09, 12:42 PM
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Amana Air Command Blower Vibrates

I have been working on the blower on our furnace and still have problems. I have taken the blower apart several times and may be messing up new things as I go, but here is where I am with the thing.

The "squirrel cage" fan wheel is not spinning straight it wobbles from side to side about inch or so and I believe this is the source of the vibration. If I run the furnace it starts out sounding okay but then vibrates more and more. The question: why is it wobbling? Here is the state of my components.

* FAN WHEEL: I took the fan wheel off the shaft and it seems okay it rolls straight on the floor and otherwise does not look bent.

* MOTOR SHAFT: When I put the setscrew in before I didn't realize it had to rest on the flat part of the shaft, and now the shaft is kind of "dug into" at that point.

* THING BETWEEN MOTOR AND FAN: This goes over the shaft. It is 2-inch diameter washer-like part except the inside hole isn't round it has six sides so it sits next to the motor and doesn't move. I am not sure if it touches the fan, but it might it looks pretty worn. (The guy at Ace Hardware thought it might be a slip disk?) It is black and looks like metal with a very hard rubber-like layer on the outside. It is about 1/4-or 3/8-inch thick and looks worn. I want to replace it but I think it will be a problem to get this myself.

* BELLY BRACKET MOUNTS: Three bolts hold the motor on the blower housing. While working on this I stripped out two of them so they won't tighten like they did. However, I was able to put a nut on the other side so I can tighten the motor down. I don't think this is the problem, unless there is enough "wiggle room" now that the motor doesn't stay tight.

* MOTOR MOUNT IN BRACKET: I just watched a little video on replacing the motor and realized that maybe my motor isn't mounted tightly in the bracket. Could this be the problem?

Any advice would be appreciated!
 
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Old 02-15-09, 12:32 PM
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Fan Vibration

The rubber part you describe is a motor mount. They are used on a different kind of mounting bracket. In your case if it were not even there it wouldn't matter.

If the fan rolls true it's not bent. About the only other thing with the fan itself could be a missing balance clip.

I suspect the problem is with the motor, worn bearings. Remove the fan from the motor & the motor from the housing. Try pulling on the motor shaft. If there is more than a trace of play the bearings are likely bad.
 
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Old 02-15-09, 02:11 PM
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Have you taken the whole unit to ACE and showed the (friendly, helpful?)guy how it behaves? You'd think someone could spot the cause. Bearings, balance, or no longer geometrically parallel between it's axis and outer wheel (this would be where if you took a 5/8ths rod, say 10 feet long, and put it through the center hole, and then layed another 10 foot straight edge across the outer wheel, so the straight edge were over the rod - that if you measured between the two, at the left end of them, and measured between the two at the right end of them, the measurements, rather than diserably being equal, would be way off. You'd have to test with the straight edge in various locations across the top of the wheel.)<-------If that were the case, say if the blower wheel was flimsily made, you may be able to correct this by grabbing the outer wheel edge and forcing it more true.
 
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Old 02-15-09, 07:49 PM
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I'm pretty sure I know whats going on. Take it apart (again) and look at the squirrel cage. In the center you see the hub that connects to the motor shaft. Then you have the solid "spokes" that connect the hub to the fins. Where the spokes contact the fins, they are supposed to be crimped or welded tight. If there is any play at all, there will be noise and vibration. If this is the problem, a replacement squirrel cage is not expensive. Maybe 30- 60 bucks.
 
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Old 02-15-09, 07:59 PM
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What model Air Command do you have?
 
 

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