Humming noise when air handler kicks in

Old 08-24-10, 09:32 AM
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Humming noise when air handler kicks in


I have an annoying low pitch humming noise whenever the air handler turns on. The noise is coming from the unit in the attic but can be heard throughout the house. The A/C technician has already come out and replace the motor but the noise is still there. It only comes on right when the air handler starts blowing.
Any suggestions?


Last edited by redfish99; 08-24-10 at 09:59 AM.
Old 08-24-10, 01:55 PM
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Could be fan bearings, an air leak in the ductwork, or a vibration. The way to tell is to get up in the attic and find out. Take a stick to connect your ear to various potential noise sources. If you can't pinpoint the noise from the outside of the air handler, you'll need to open it up.
Old 08-25-10, 08:43 AM
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Probably just a baffle plate loose inside the unit. You need to dissassemble and add/tighten all fasteners I also like to add a bead of Vulkem 116 to all the seams and let it cure for 24 hours before startup. I pity the guy that tries to take it apart later though LOL the Vulkem is some kinda good stuff.

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