Noisy condenser fan

Old 09-20-02, 05:43 PM
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Question Noisy condenser fan

The fan in one of two outdoor A/C condenser units recently started making a loud fast rattling noise. Sometimes it is intermittent and sometimes continuos. I cannot find anything loose or the source of this noise. It seems to be coming from inside the fan . Any troubleshooting tips? Thanks for your help.
Old 09-20-02, 05:51 PM
hvac4u's Avatar
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the bearings going out, does the motor feel hotter than the other one? make sure all brackets, screws and bolts are tight. have tightened housing and cured this problem after another tech condemned the motor.
Old 09-20-02, 05:57 PM
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If the bearings are fixing to die, do I have to buy a new fan motor or can I rebuild it? I will check to see if it runs hotter than the other one. Sometimes I think that the noise is coming from the condenser itself...are there any moving parts in there?
Old 09-20-02, 07:42 PM
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No moving parts but sometimes the screws work loose or the fan guard vibrates. Try turning the fan blade by hand with the power off. Is it stiff or can you feel some grinding? Fan motors are usually made with sleeve bearings and are replaced if the bearings go out. It's also possible that the fan blade has developed a crack. Look it over closely.
Old 09-21-02, 04:01 AM
Jacque Schidt
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It's amazing what some lubricant can do. If the motor has oil ports, use the thickest NONDETERGENT oil you can find. If not, take the endbells off and oil the wicks with a good heavy lubricant.

Checking those fan blades is also a good idea.

Most outdoor fan motors need oiling once a year or so, and even the ones that are "permanently lubricated" need oil every four or five years.
Old 09-21-02, 06:36 AM
Jersey Devil
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Heck, if you are going through all that trouble, change the motor, they are not that expensive. Your bearings are shot inside the motor or they are on their way. Correct me if I am wrong Frenchy

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