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  1. #1
    Join Date
    May 2010
    Location
    oklahoma
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    12

    unit needs resetting over and over??

    Can anyone help with this one? I have this 12 ton carrier package unit that has a call for cooling but compressors arent running or outdoor fans. I got voltage but contactors are not engaging. I was told to just hit the disconnect and give it five minutes and turn it back on and it will run. I took a look at it and and found the contactors wont pull in, with a little nudge they suck right in. any ideals what i can look for. model number 48 HJF 012 571HQ thank you for any help.

  2. #2
    Join Date
    May 2007
    Location
    Dry as a bone Tucson
    Posts
    4,276
    Check your voltage drop to contactor. Check conductor size.
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  3. #3
    Join Date
    Oct 2009
    Posts
    28
    Sounds like a bad contactor coil to me.

  4. #4
    Join Date
    Jun 2009
    Location
    Bakersfield, Ca
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    1,716
    Quote Originally Posted by invisiblecollar View Post
    Sounds like a bad contactor coil to me.
    Sounds like low line voltage to me. time for a new transformer?

  5. #5
    Join Date
    Nov 2000
    Location
    Hoggtown! Toronto, ON
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    1,133
    Quote Originally Posted by DavyB View Post
    Sounds like low line voltage to me. time for a new transformer?
    I remember once where the unit was rated for 208v or 240v. The transformer had spade connectors that could be set for either voltage. Same problem as the OP described was happening. Turned out it was the transformer. 208v was supplied but the transformer was wired for 240v. Not enough voltage to pull in the contactors.

    However this one is a 12 ton so its probably 208 or 575 3ph. I'd still be looking at the transformer...
    "...refresh my memory. When did I start caring about this stuff...?"

  6. #6
    Join Date
    Apr 2010
    Posts
    21
    JettaKnight,
    Yes it can happen my friend

  7. #7
    Join Date
    Jan 2010
    Posts
    6,206
    Quote Originally Posted by Jettaknight View Post
    I remember once where the unit was rated for 208v or 240v. The transformer had spade connectors that could be set for either voltage. Same problem as the OP described was happening. Turned out it was the transformer. 208v was supplied but the transformer was wired for 240v. Not enough voltage to pull in the contactors.

    However this one is a 12 ton so its probably 208 or 575 3ph. I'd still be looking at the transformer...
    Jetta,
    It's a 10 ton unit 012 equals 10 ton by Carrier's nomenclature. ( It's a carrier thing ) Your right about the trasformer line taps. I see that mistake often. Also i believe he said it was 480 volt 3 phase.

  8. #8
    Join Date
    May 2010
    Location
    oklahoma
    Posts
    12
    i have high voltage and good low voltage to contactor and its not just one contactor its both compressors and outdoor fan contactor

  9. #9
    Join Date
    May 2010
    Location
    LAS VEGAS
    Posts
    18
    Quote Originally Posted by garytulsa View Post
    i have high voltage and good low voltage to contactor and its not just one contactor its both compressors and outdoor fan contactor
    I am not the greatest trouble shooter for sure - but if you have good control voltage, and the coil is not engaging enough to close them, I would think either something wrong with contactor coil -- or more probable as you said someone suggested in your previous post Loose connection somewhere-- possibly the board has a setting of higher than 5 minutes before it can be turned back on ???

  10. #10
    Join Date
    Sep 2006
    Location
    Ohio
    Posts
    464
    Quote Originally Posted by garytulsa View Post
    i have high voltage and good low voltage to contactor and its not just one contactor its both compressors and outdoor fan contactor
    Just so I have this right. With a call for cooling you have good low voltage at the contactors but they are not pulled in. If this is the case, I would replace one of the contactors and see if it works.
    Are you sure you didn't check the voltage at the contactor while it was pulled in?

  11. #11
    Join Date
    Jan 2009
    Location
    Indiana
    Posts
    3,228
    i am thinking its your transformer. u may have 24 Volts but the VA may have dropped..Enough voltage to do the job just just not enough ass behind it.

  12. #12
    Join Date
    Nov 2006
    Location
    Southeastern Pa
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    18,232
    Quote Originally Posted by yellowirenut View Post
    i am thinking its your transformer. u may have 24 Volts but the VA may have dropped..Enough voltage to do the job just just not enough ass behind it.
    By that, the meaning is that you can have 24 volts all day, but a high resistance in the circuit can limit current flow, and that will keep a contactor from pulling in, even when the CLO is not an issue.
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  13. #13
    Join Date
    Jun 2009
    Location
    Bakersfield, Ca
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    1,716
    Quote Originally Posted by yellowirenut View Post
    i am thinking its your transformer. u may have 24 Volts but the VA may have dropped..Enough voltage to do the job just just not enough ass behind it.
    Right, you need va. behind your voltage and if the transformer doesn't have the balls anymore, you know what you gotta do.

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