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    kat1214's Avatar
    kat1214 Posts: 2, Reputation: 1
    New Member
     
    #1

    Mar 3, 2009, 03:33 PM
    Rheem Central A/C Unit -- Outside Fan Runs Constantly
    Our unit is a RHEEM Classic and was manufactured in 2000. Model #RAMB-048-JAZ

    The outside fan never turns off. The inside unit runs as it should and cycles on and off appropriately and the A/C cools great. The problem is that we have to go out and remove the disconnect (breaker) outside in order to stop the fan from running. As soon as we plug it back in, the fan starts right up even if the thermostat is set to OFF. Today we replaced the thermostat at the suggestion of a HVAC tech friend. (Does not live close enough to help out hands on) and this did nothing to solve our problem.

    We have replaced the outside fan motor, the fan capacitor, the fan relay and the main relay. The compressor cycles on and off and you can see the relay pop in and out as it should. The only thing left outside is the compressor (which is seemingly fine) and the run capacitor. The new fan had to have it's own capacitor instead of being wired to the old capacitor. The old capacitor now connects to the compressor only.

    We are out of ideas and so is everyone around here. Please let me know what else we can provide you with in order to troubleshoot. Thanks in advance for you help.
    eschuen's Avatar
    eschuen Posts: 62, Reputation: 6
    Junior Member
     
    #2

    Mar 3, 2009, 05:09 PM

    Sounds to me like you've re-wired that thing wrong. You have a contactor with a solid leg and I believe you have that 110 volt fan motor wired on that leg
    wmproop's Avatar
    wmproop Posts: 3,749, Reputation: 91
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    #3

    Mar 3, 2009, 05:16 PM
    Does sound like maybe a stuck contactor,, but I doubt the condenser has a 110 volt motor,, condensers are 220-230 volts,, be sure you have killed the power before you start messing with it
    eschuen's Avatar
    eschuen Posts: 62, Reputation: 6
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    #4

    Mar 3, 2009, 07:15 PM

    I didn't go with a stuck contactor because he said the compressor was OK and just thought that maybe the fan was 110 since it was running without a problem. His best bet is follow the power to its source as something is wired wrong... ya think?
    kat1214's Avatar
    kat1214 Posts: 2, Reputation: 1
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    #5

    Mar 3, 2009, 07:36 PM
    Quote Originally Posted by eschuen View Post
    I didn't go with a stuck contactor because he said the compressor was ok and just thought that maybe the fan was 110 since it was runing without a problem. His best bet is follow the power to its source as something is wired wrong.........ya think?
    Here's my question on this though... the A/C worked fine all the years that we've owned our home (5) and it just began doing this a few weeks ago. Being that it's been cool, we are just now addressing the issue BUT... both the old fan and the new fan are doing the same thing. Doesn't that mean that it would not be a wrong wiring issue? Since it worked before. IDK... I'm at a loss here. Thanks for the comments. Any ideas help.
    mygirlsdad77's Avatar
    mygirlsdad77 Posts: 5,713, Reputation: 339
    Plumbing Expert
     
    #6

    Mar 3, 2009, 07:57 PM

    Please take a picture of the contactor on outside unit. Your problem most likely lies hear unless something is wired way off base. It is possible that you are getting 110 to compressor and fan motor due to a bad contactor, but only the fan is running( at a slower speed). Check to see if fan runs faster when a call for ac(when compressor kicks on). Please let me know what you find. I have never seen a condenser fan that wasn't controlled by the contactor, so somehow power is getting through that contactor to fan motor. The 110 may run fan motor(like I said at a slower rate), but won't start compressor..
    KC13's Avatar
    KC13 Posts: 2,556, Reputation: 99
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    #7

    Mar 3, 2009, 09:00 PM
    I've seen this one before. In my case, it was the compressor. Partially shunted windings were back-feeding voltage to the motor without overloading and tripping the circuit protection. Use a clamp-type ammeter to check for current in the compressor leads when the fan is running and the compressor isn't.
    Pakabears808's Avatar
    Pakabears808 Posts: 1, Reputation: 1
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    #8

    Nov 14, 2011, 05:14 PM
    (quoting KC13)
    I've seen this one before. In my case, it was the compressor. Partially shunted windings were back-feeding voltage to the motor without overloading and tripping the circuit protection. Use a clamp-type ammeter to check for current in the compressor leads when the fan is running and the compressor isn't.

    My friend is having the same problem. What did you do to resolve this problem after troubleshooting? Did you need to replace any relays, circuit board or the compressor?

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