Central AC not cooling


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Old 08-20-14, 06:01 PM
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Central AC not cooling

Our central AC is blowing but not cooling. Checking system I found the condenser fan is not running. The unit is buzzing and the fan motor itself feels hot but is not running. The fan blades are not locked and turn freely.

Bad fan motor?

RUUD Model UAKA-030JAZ

Thanks in advance for any assistance.
 
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Old 08-20-14, 06:23 PM
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It may be as simple as a bad capacitor or a possible defective fan motor.

The capacitor is relatively inexpensive in the grand scheme so it usually gets replaced first.
 
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Old 08-21-14, 09:44 AM
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Pulled the cover off this Ruud unit and the run capacitor was right there on top next to a contactor switch. Got a new one(Made in China! ) from the local appliance parts store and plugged it up and the unit is running fine.

Next question: The contactor is buzzing fairly loud, is that ok? Unit seems to be cooling fine which is good since the next 2 days we'll see 96 degrees here in west GA!

Thanks for the help!
 
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Old 08-21-14, 10:21 AM
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I would replace the contactor, buzzing is not good. Be sure and turn off power to the inside unit when you replace it. And of course pull the disconnect on the outside unit.
 
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Old 08-23-14, 11:11 PM
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Thank You! I'll do this Monday AM. Plug and play, correct?
 
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Old 08-23-14, 11:40 PM
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Pretty much plug and play. You may find slight differences.

I highly recommend some very close well lit pictures in case of problems.
 
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Old 08-25-14, 10:38 AM
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Okay, I have contactor coming from Amazon for $20, Protech unit single pole, 24v, 30 amp. I've also ordered a contactor and capacitor for my own unit also since its 13 years old and will replace these parts proactively. My unit is the same model only smaller(2 ton) than my sister's(2 1/2 ton) and uses the same parts.

I've made a drawing of where all the wires hook up on the old contactor, 2 questions though:

1) Do I need to discharge the contactor before removing it?

2) When discharging the capacitor, should I notice any spark or arc or anything when shorting out the 2 poles? When I shorted the 2 poles on the first capacitor to change it, there wasn't anything noticeable?
 
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Old 08-25-14, 11:10 AM
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Since the motor windings are always attached to the capacitors the charge bleeds down by itself.
It's normal to see no spark. We only short the cap out as an added safety measure just in case.

When replacing the contactor make sure power is turned off to the condensor as well as to the air handler. You don't want to short out the 24vac control lines. You should also discharge the cap too.
 
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Old 08-25-14, 11:12 AM
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You don't need to do anything with the contactor. You probably won't see any sparks on the cap.
 
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Old 09-05-14, 09:57 AM
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OK, both units(Ruud 2.0 and 2.5 ton) have new contactors and new capacitors and seem to be running good. Some observations:

1) My sister's 15 yo 2.5 unit was easy. Both capacitor and contactor changed out with zero issues.

2) My 13 yo 2.0 unit was a tad trickier. First when changing the contactor, I noticed the wire connections(spades) on the new contactor felt pretty loose. Used my needle nose pliers to crimp the spades slightly to insure a good snug tight fit. Second, the capacitor I first got which was identical to the one that worked on my sister's unit was much fatter around than the original. So ordered a slimmer 2 inch diameter one with same specs, 35/3 mf and 370v. It arrived, looked like same size when I eyeballed it before disconnecting wires. Then found it was just a hair too big to slide into the sheet metal hole where the original rested. Used my flat metal file to slightly enlarge the hole and it slid in.

Thanks all for the good advice, especially on necessary power disconnects and discharging the caps. I also made drawings of all the wire connections before unhooking anything and double checked all my work at the end before powering units back up.
 
 

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