AC issues, fan stops

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Old 08-12-14, 01:13 PM
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AC issues, fan stops

I've had this issue over the last two weeks. During the hottest time of the day, the temps in the house will slowly creep up into the low 80s. I'll go check and the fan outside is not spinning. Sometimes I can hear a buzzing noise and spin it up manually and it will stay on. It will run like this for a while until the unit shuts off when it reaches the desired temp or I notice it getting hotter and see that it's stopped. From there at some point it will stop and then no buzzing and I can't start it unless I leave the unit for for a few hours.

I have replaced the capacitor and fan motor and it's still doing the same thing. Looks like the thermal protection is kicking in but why? What else could it be? The only common thing is that it happens during the day when it's really hot outside. We have gotten by with a window unit in one room and a box fan on top of the condenser and keeping it at 78ish.
 
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Old 08-12-14, 01:24 PM
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The symptoms you described (fan won't start, but will run if you give it a push), are typical of a bad capacitor. However, you said that you replaced both the motor and capacitor. Are you sure that you have the motor/capacitor wired correctly? Many replacement motors require a different capacitor wiring, however the motor should have come with a wiring diagram.
 
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Old 08-12-14, 01:27 PM
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It will run on its own if it starts cold. I put it on last evening and it worked just fine until just about an hour ago. It's all wired properly. It's strange because the cap tested bad when I went to buy the new one. So I thought for sure that was it. It's doing the same thing with a new motor and cap now so I'm at a loss.
 
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Old 08-12-14, 01:38 PM
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After the fan motor shuts down, have you tried feeling the temperature of the motor to see if it feels hot? It should be warm, but not HOT. If it's getting hot, and it's wired correctly, I'm guessing that the motor may be defective (may have a shorted winding).
 
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Old 08-12-14, 01:49 PM
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Perhaps but it would be odd to have two motors and capacitors doing the same thing. Now I did do the cap first and after about a week, I did the motor too would having a new cap on with a bad motor cause the cap to go bad? Could this have anything to do with the contactors? Low freon causing the house to take too long to cool causing the motor to run so much and long that it over heats and shuts off?
 
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Old 08-12-14, 02:03 PM
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It sounds like you used the same "new" capacitor that you bought for the original motor with the replacement motor. Does the new motor require the same value capacitor as the original motor? Many times, the replacement motor requires a different value capacitor. If you're using the wrong value capacitor, that could cause the new motor to overheat. The system being low on refrigerant wouldn't cause this issue. Theoretically, the compressor/condenser fan should be capable of running non-stop without overheating (assuming proper installation).
 
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Old 08-12-14, 04:48 PM
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Is this a reversible motor? Make sure it's running in the right direction.
 
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Old 08-12-14, 07:05 PM
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The cap is the same one 7.5 370. The motor is not reversible and is turning the right direction. I'm at a loss and am about to call in a pro.
 
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Old 08-12-14, 07:15 PM
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Someone asked you in a previous post if the motor was getting hot.
From what you are describing it is. Why...... that's the question.

Are the coils clean on the condensor unit ?
 
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Old 08-12-14, 07:30 PM
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I haven't messed with it today so I'm not 100% sure on that but the old one was. It would get very very hot. So far with it set to 78 it seems so be running ok. Any lower and it breaks. I hosed them off but clean clean I don't know.
 
 

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