Vibrating noise from bathroom exhaust Fan

Old 12-18-22, 02:23 PM
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Vibrating noise from bathroom exhaust Fan

My daughter is complaining that she has a noisy bathroom fan. I open the cover, clean it thoroughly and checked out the fan, and found no problem. The path to the outside is also clear. But she said the problem is still there. I finally found out that the vibration noise only comes when the door is closed. The reason why I did not see the problem was I had the door open when I was working on it. I am trying to understand why the vibration only comes when the door is closed. Does the fan have to work harder when the door is closed? The fan (90 CFM) and old and I want to replace it with a 110 CFM fan anyway. If the size of the room and the closed door has an impact on the running of the fan, I like to understand the reason before I buy a new fan that may not be any quieter.
Old 12-18-22, 03:11 PM
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If the squirrel cage is plastic, it could be spinning on the shaft. I've had several that have done that. The shaft has a flat half, and the plastic cage fits that shape... until eventually it gets rounded out, then it wants to spin on the shaft, vibrate and only runs at 75% speed while making noise. And yes, if the door is closed it makes it work harder, especially if you have less than a 1" gap under the door.

So pull the keeper washer off, pull the squirrel cage off and check to see if the hole in the squirrel cage is rounded out. If it is, you can get a replacement.

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