A/C unit shaking

Old 05-21-17, 09:58 AM
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A/C unit shaking

Quick question. I had my ac fan motor replaced yesterday with my home warranty due to previous one went out. After they put in a new fan motor and turning it on the whole unit was shaking very bad. The company that installed this new fan motor motor said this unit was just making noise due to to original ac casing. My question is what would cause something like this? It never did this before. Nobody else's ac units are this loud nor do they shake like this does. The guy that did the install said to put something heavy on it to prevent the shaking. So I'm wondering if the following. It's either an unbalanced motor, or it's wired out of phase. Like it's a 3 phase motor running on only 2. But, most likely just unbalanced.
Or, it's a faster motor, and the housing can't handle it.

Old 05-21-17, 10:07 AM
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Sounds like they either bent fan blade or knocked it off balance. Have them come back and fix it. Call warranty comp. and complain.
Old 05-22-17, 05:49 AM
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You would expect a fan motor replacement to be a relatively simple task.
In many cases the fan collar is fused to the motor shaft with rust and proper pullers and skill are often needed to remove the fan without damage.

You can check for an unbalanced fan by ensuring the power is off and spinning it by hand and comparing the height of each blade.
This is how a blade can be rebalanced by carefully bending each blade into alignment.

The one who bent them should know how to do this.
Old 05-22-17, 06:24 AM
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Many times, you'll find that home warranty services will send out the cheapest "body" possible. A family member used one and they were installing used parts on top of taking 4 months to fix the issue, which still isn't really fixed.
They likely bent the blade. This will destroy the new motor.
Old 05-22-17, 07:24 AM
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Try not to use home warranty if you can. AC firms signed up with home warranty are paid much less (about 50%). 8 out of 10 home owners have had bad experience with home warranty. So, don't use home warranty ...

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