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  1. #1
    Join Date
    Jun 2006
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    48

    Jammed reversing valve?

    Heat pump quit heating in late winter - has sat unused since. Technician attended a few days ago and discovered that the unit has no charge and that it had been released through the "safety plug", which blows-out once it reaches a certain temperature. With the system idle (just AH blower running) a pronounced hum was found to be coming from the reversing valve solenoid.

    In addition to the humming, the solenoid becomes hot to the touch and vibrates at a high frequency. With it powered, I disconnected and re-connected the solenoid coil lead and heard a pronounced click from the reversing valve. I assume there is at least some motion.

    The unit (a Carrier) failed during the heating cycle. Does this tend to indicate a jammed valve or a faulty solenoid?

    Thanks so much,
    Kris

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,337
    Neither.

    Its humming because its energized.
    Its hot because its energized. (Its consuming electric, so it makes heat.)
    It should make a click when its denergized, and when its renergized.
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  3. #3
    Join Date
    Jun 2006
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    Quote Originally Posted by beenthere View Post
    Neither.

    Its humming because its energized.
    Its hot because its energized. (Its consuming electric, so it makes heat.)
    It should make a click when its denergized, and when its renergized.
    It was a loud humming - unusually so. Even with the other AH running, we could hear it.

  4. #4
    Join Date
    Dec 2006
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    Fayetteville,Arkansas
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    1,427
    The solenoid is energizing but the actual valve is not moving. You should hear a swoosh sound to go along with the clicking noise.
    If you choose not to decide you still have made a choice.

  5. #5
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    Jun 2006
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    Quote Originally Posted by hvaclogic View Post
    The solenoid is energizing but the actual valve is not moving. You should hear a swoosh sound to go along with the clicking noise.
    I hear a click as in something moving around in the R valve body and maybe hitting the end of the horizontal tube.

    If I have the tech come back, would he be able to check if its working properly or no?

  6. #6
    Join Date
    Apr 2005
    Location
    NE PA
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    698
    Safety plug which blows out...I don't think so. There may be a high pressure cut off switch, but no blow out plug. If you lost refrigerant, you have a leak. It may be fixable, maybe not. As far a the reversing solenoid, what was already said is correct. It will likely hum when energized (usually for cooling) and it will get hot to the touch...normal.

    Get another opinion.

    paul

  7. #7
    Join Date
    Jun 2006
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    48
    Quote Originally Posted by tecman View Post
    Safety plug which blows out...I don't think so. There may be a high pressure cut off switch, but no blow out plug. If you lost refrigerant, you have a leak.
    On this point, I must disagree. As to the second opinion, well, that is a given!
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  8. #8
    Join Date
    Apr 2005
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    NE PA
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    Not common in resi units.

    paul

  9. #9
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    Aug 2006
    Location
    Marco Island, Fl
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    729
    That safety plug is a simple repair. I beleive it screws in.
    Of course, have them replace the liquid line filter/dryer.

    Those old Carrier 3 piece splits did a great job. I would guess its from around 1988 or so.

    The safety plug needs to be replaced, and not soldered over as I have seen done before. Your inoor compressor/r-valve/control section can be valved off, making the safety plug a requirement.

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,337
    He won't hear a swoosh sound since its out of gas.

    RV can't be checked until the system is recharged.
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  11. #11
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    Mar 2005
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    burlington county n.j.
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    Quote Originally Posted by tecman View Post
    Safety plug which blows out...I don't think so. There may be a high pressure cut off switch, but no blow out plug. If you lost refrigerant, you have a leak.

    Get another opinion.

    paul


    it was common to have those blow outs on carrier units, i have seen them on straight cool split and package units.


    MANY of the round residential units had them.

  12. #12
    Join Date
    Dec 2006
    Location
    Middle Tennessee
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    11,347

    *

    the safety plug may have been doing its job

    you need to find out why it blew!



    .

  13. #13
    Join Date
    Jun 2006
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    Quote Originally Posted by Airmechanical View Post
    the safety plug may have been doing its job

    you need to find out why it blew!

    .
    What does your intuition say?

    The tech who visited here had no idea and didn't seem interested in finding out. He just told us a salesman would come by tomorrow morning...

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