Lennox Condenser Vibrating Badly

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Old 12-09-18, 09:23 PM
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Lennox Condenser Vibrating Badly

I have what I consider to be a heavy vibration in the condenser in our split-system, all-electric HVAC. The condenser is a 20 SEER Lennox system. So far, the contractor has been unable to repair the problem. If you look at the video, it seems obvious to me; the fan needs to be balanced.

Here is the video: https://youtu.be/Si36eu2s-O4

The fan is this one: https://www.hvacpartsshop.com/93m97-...-fan-assembly/

Looking at the fan, it appears that it allows for weights to adjust the balance of the fan. I don't think I need to replace that. However, if I don't fix it soon, I think things will start failing (metal fatigue). System is still under warranty, and this is an expensive impeller. I think the installer needs to repair this.

Any advice as to how to proceed further?
 

Last edited by MikeM95831; 12-09-18 at 09:50 PM.
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Old 12-09-18, 11:57 PM
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Welcome to the forums.

Sorry..... it's not obvious in the video that the fan is out of balance. Some vibration..... especially on the fan grill..... is normal. It's next to impossible to re-balance fan blades. If they are out of balance they'll need to be replaced. Those weights are put on in the factory.


So far, the contractor has been unable to repair the problem.
What does the contractor say the problem is ?
 
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Old 12-10-18, 10:22 AM
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I don't buy it. There is a loud buzzing throughout the house that precisely parallels the vibration at the condenser. You can feel it in the lineset as it enters the air handler.
 
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Old 12-10-18, 09:59 PM
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You'd be more likely to feel the vibration of the compressor than from the fan.
 
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Old 12-11-18, 01:44 AM
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I agree that the video and the cup of water does not show much.
If the source of the vibration is the fan blade it is more likely to be bent rather than be out of balance.
A way to tell if it is bent is to first turn off the cct breaker.
You would take 2 narrow flat blade screwdrivers and put one through the fan guard until it just clears the end of the blade.
Hold it firmly against the guard then with the other screwdriver slowly move the blade so you can compare the height and position of each blade.
It is like checking a spoked bicycle wheel for alignment.
You can move the position of the indicating screwdriver to get a good feel if there is a problem with a blade or blades out of position or even a bent motor shaft.

If one or more blades are out of whack and the blade is aluminum it is possible to gently bend things into shape.


Another test is to disconnect the fan motor and BRIEFLY operate the unit to see if it is the compressor causing the problem.
 
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Old 09-24-19, 04:46 PM
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Sorry for my delayed response.

It turns out there actually was a problem with the installation. The contractor overfilled the refrigerant, which resulted in too much pressure in the system. They had to remove approximately 10% (1.5 lbs) of refrigerant from the system.

Since they did that, the system is much quieter. What's more, the compressor unit would shut down at approximately 45 Fahrenheit, which would cause the auxiliary heat to come on. My March bill was atrocious, nearly $500. Since then, I've caught up and passed my anticipated steady-pay amounts on my SMUD bill, so I'm sure they'll reduce my bills for next year when they review my usage.

In short, system is now whisper-quiet in the summer, a bit noisier in the winter (but not much), the house is more comfortable, and my bills have dropped. The contractor did this free of charge, which I appreciate.
 
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Old 09-24-19, 04:57 PM
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The contractor did this free of charge, which I appreciate.
Good thing as it's pretty embarrassing. That is an expensive set up.

Thanks for letting us know how you made out.
 
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