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  1. #1
    Join Date
    Sep 2002
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    new compressor won't run - how come ?

    4' deli display case with gravity coils. About 3-4 years old.

    Originally: case was warm - compressor won't start.
    Add 3n1 kit - compressor stuck - compressor cycles on O/L
    Replace compressor - old & new are both TPCo AKA4460YXD
    New compressor starts and runs but immediately pulls 7.8A (about 7.0 FLA rating) with partial charge. Runs lumpy / shakes like the start winding is staying in. By the time I get the S wire off the compressor terminal the compressor too hot to recycle. It's already past 7:00P so I condemn the start relay and head for home.

    In the morning I take a start relay back to try, test it before installing it, and make sure all the wiring is perfect. Compressor starts and runs drawing about 5.0A but as soon as any charge is added the amps start to skyrocket: 8-9-10-11-12 and

    Head pressure is about 90 lbs. at that point with a 5 lb. suction pressure. No measure-able subcooling at the point where the amps start to spike.

    OK - so now what? <g>

    I called the TPCo tech line, got voice mail, and have yet to get a return call.

    What am I missing here?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  2. #2
    Join Date
    Aug 2012
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    Def. sounds like a restriction.
    It's not if your doing it right it's whether your doing the right thing that is important.

  3. #3
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    Thread Starter
    You're right - the world really Is tougher when you are being stupid. I know that from hard-won personal experience. <g>

    A restriction would have to be in the discharge line (where there is no way to check it <g>) or in the condenser as the liquid line pressure isn't high.

    PHM
    ------
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  4. #4
    Join Date
    Jun 2004
    Location
    Olean, NY
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    King valve didn't stick did it?

    Sent from my MZ601 using Tapatalk
    Guinness for strength

  5. #5
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    Sep 2002
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    Thread Starter
    On the receiver? I didn't even crack it until after removing the condensing unit - no way to get a wrench on the cap. Recovered through the suction service valve and then pulled the rotolocks in order to slide the condensing unit out. Then I could remove the seal cap and crack the valve off backseat. Where it still is now as I left the gauges on it. <g>

    PHM
    ------




    Quote Originally Posted by B_roche View Post
    King valve didn't stick did it?

    Sent from my MZ601 using Tapatalk
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  6. #6
    Join Date
    Nov 2001
    Location
    Seattle, WA
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    What kind of refrigerant? Perhaps the old compressor ran too hot for too long and tuned the oil/refrigerant into mush/goo.

    Take the refrigerant out, start the compressor and let it run for a minute to see if it runs normal with low amp draw for a minute of so. If so then something is loading up the high side of the compressor with a proper charge which would be in the order of a restriction, me thinks.
    "The American Republic will endure until the day Congress discovers it can bribe the public with the public's own money.
    - Alexis de Toqueville, 1835

  7. #7
    Join Date
    Mar 2011
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    It may be time for a piercing valve on the discharge line before anything else. Only takes a minute.

    Is this a capacitor start and run compressor with a potential relay? Seems like I remember that model # from 2 door beverage coolers. It must be larger than the small fractionals with the current relay just bringing in the start winding. Is that correct?

  8. #8
    Join Date
    Mar 2011
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    There may still be an electrical problem, but does sound like a restriction upstream of the liquid line, those will raise the current consumption in a heartbeat.

    This reminds me I had one of those compressors do this to me on a replacement (2 door beverage cooler) it took a while to nail because I didn't want to suspect the new compressor. I repeatedly checked flow through the system with it open, re-sealed and charged again, checked all the electrical components several times, finally exchanged the compressor and put the new one in with another new cap tube drier and real good evac, the second can ran sweet.

  9. #9
    Join Date
    Jun 2004
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    Olean, NY
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    Actually I meant on the discharge. It's a very dumb question but since it took like....none almost, I lobbed that one out there for ya

    Sent from my MZ601 using Tapatalk
    Guinness for strength

  10. #10
    Join Date
    Dec 2010
    Location
    Savannah Ga.
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    Sounds like blocked discharge line or supply house gave you wrong voltage replacement? You have checked volts already I assume? Good luck with it!

  11. #11
    Join Date
    Mar 2013
    Location
    Central IL
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    You may want to reclaim system and flush. could be the old compressor slugged oil through out system.

  12. #12
    Join Date
    Sep 2002
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    Thread Starter
    The original compressor had all it's oil in it when removed - or pretty close anyway - and the oil looked and smelled pristine when removed. The compressor froze mechanically solid and I have no idea why. The customer said that it never made any unusual noises before stopping.

    I have no idea why the new compressor spiked it's amps with just a partial charge and loading but today I installed another new compressor and it started and ran and performed perfectly.

    So I just don't know what was wrong with the first new one. I turned it in as defective / warranty and the new one ran perfectly well. The only other thing I changed was the drier.

    It's not a great mechanic's conclusion but I got this call last Sunday - and enough is enough. <g> That must be some kind of record I guess: a full week to change a 1/3 HP compressor! <g>
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  13. #13
    Join Date
    Mar 2011
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    Thank ya for the update

    I experienced the same

    Maybe the cylinder was a lil tighter than expected...

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