Balancing a blower wheel

hvac1000 · Feb 7, 2009, 05:17 PM

Many times a wheel will have a wobble and since it is caused by the shaft bushing being off center or pressed incorrectly it is just about impossible to fix without the possibility of making it worse. Now if the blower wheel is out of balance take it back since trying to balance the wheen with the shim clips is done by a special maching and I have never been able to rebalance on in the field accurately.

mygirlsdad77 · Feb 7, 2009, 05:41 PM

I wouldn't worry about it if it is a very minor wobble. Not much you can do about it. If motor and wheel were replaced, and installed correctly, then you should be fine. Let me know why you are worried about how the motor is mounted. Is the mount not secure(stripped mounting bolt? Or other problems with install?) I would say you will be okay as long as its not shaking the furnace.

atrain · Feb 8, 2009, 05:26 AM

Quote:

Originally Posted by mygirlsdad77

i wouldn't worry about it if it is a very minor wobble. Not much you can do about it. If motor and wheel were replaced, and installed correctly, then you should be fine. Let me know why you are worried about how the motor is mounted. Is the mount not secure(stripped mounting bolt? Or other problems with install?) I would say you will be okay as long as its not shaking the furnace.

The motor mount is secured correctly, however I did have a stripped bolt hole. The reinforcing piece of metal on the underside of the sheet metal blower assembly would no longer accept a 1/4 inch bolt. I drilled and tapped one size larger and the problem was quickly solved. I do not think this has to do with the wobble. I do not believe any of the bolts are overtightened.

I would have thought a new blower wheel would rotate smoothly, not with a wobbly rotation. Apparently this is not uncommon? Vibration on all speeds is minor, although no vibration at all is obvously preferred.

hvac1000 · Feb 8, 2009, 05:36 AM

Its all the China junk. Years ago a blower wheel ran true with no movement or vibration. Not any more today. I need a new wheel for my home made air handler unit 5 years ago. I went up to the supply house and started looking. After I went and checker 5 or 6 of them I finally found a perfect one. What a pain. I took my pointed triangle base with the 1/2 inch adapter to do the tests with. The sad part is they no longer even make that tool for the trade to test with.

Balancing a blower wheel

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