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  1. #1
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    AJA4512AXD - shell suction or internal piped ?

    40º walk-in with a failed, two year old, AJA4512AXD. Mechanical - stuck - LRA only.

    Evap about 4' higher than condensing unit with the only suction-rise being about 15" off the evap coil and out the top of the box.

    I have decided I like R-134 better than the blends for R-12-esque jobs.

    Because I had the new compressor out in my hands I wanted to dump out the AB oil and install 22 ounces of POE - to run under the R-134.

    For some reason I decided to also pour out he filed compressor's oil. Which, btw; was Pristine looking. My issue is that I could only get 2-3 ounces out. The idea that 20 ounces is 'stuck' somewhere out in this tiny 1 HP system just seems unlikely to me so my question is:

    Does this compressor have just a shell-stub suction connection? Or on this old style compressor was the suction hard piped internally from the inner wall of the shell over to the suction inlet port?

    Can that be why I can't pour out the oil?

    Damn! I could have Weighed the two compressors to see if the oil was in there!!! I didn't think of that until just this second!!

    Oh well; too late now. <g>

    So? Does anyone know what this particular TPCo's internals look like?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  2. #2
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    Thats just an outer shell. No tubing.

  3. #3
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    You may have 20oz in the system.

    But why?

  4. #4
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    Thread Starter
    Hmmmm . . . . so no oil to remove from the old compressor. And an apparent mechanical failure. Available failed-compressor oil looks brand new. No oil puddles or leaks anywhere . . . so . . . . where the hell can 20 ounces of 'lost' oil be hiding in this little almost-close-coupled system? <g>

    PHM
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    Quote Originally Posted by pecmsg View Post
    Thats just an outer shell. No tubing.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  5. #5
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    Cut the shell off the old compressor with a cutting disc if you are worried the oil is trapped in there. Or drill a couple holes where your think the oil sump is on the shell.

    Sent from my SM-N910W8 using Tapatalk

  6. #6
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    Quote Originally Posted by Poodle Head Mikey View Post
    Hmmmm . . . . so no oil to remove from the old compressor. And an apparent mechanical failure. Available failed-compressor oil looks brand new. No oil puddles or leaks anywhere . . . so . . . . where the hell can 20 ounces of 'lost' oil be hiding in this little almost-close-coupled system? <g>

    PHM
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    Please let us know if or when you find it.

    Any history on this system?

  7. #7
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    A failed-open TXV would be my first guess. What else could wash out the compressor oil But liquid refrigerant?

    But 20 ounces of oil in the evap would seem like it would be damned near Filled with oil? <g> The overhead line set was dry when I had the compressor loose and replaced the driers - and typically an oil moving system has excess oil Everywhere. <g>

    That all just seems odd to me: suddenly the TXV fails-open (extremely rare to start with) - the compressor floods with liquid - virtually all the oil is foamed out - and all of it collects in the evaporator - And at the exact same moment that the compressor bearings fail and so prevent any oil from returning to the compressor. And on top of that - the refrigerant lines are somehow left dry.

    It's a little hard to accept as a valid explanation. <g>


    PHM
    --------


    Quote Originally Posted by pecmsg View Post
    You may have 20oz in the system.

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

  8. #8
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    Before I drilled the oil sump on the compressor I'd drill a hole in a low point at the evaporator...especially if the coil has a bottom feed and a top outlet. My bet is that's where the oil is.

  9. #9
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    History -

    An elderly friend of mine - lifetime in this business - took care of this seasonal account for decades. All the equipment is switched off from Labor Day to Memorial Day. My friend retired and lateral-ed the ball off to me maybe 5-6 years ago. The first time I saw it this system had a 20+ year old compressor with a slightly leaking and badly rusted suction service valve on the compressor. I topped it up with R-414 and ordered the valve. After it came in I Could Not remove the valve nut for fear of ripping the suction stub off the compressor shell. Customer chose re-fill only: let it leak.

    This year when they called to say it was down (along with six other major systems which they failed to mention until I Got there - but that's another story <g>) I arrived to find a new compressor installed. And stuck.

    The customer was a little vague on who had changed it - saying: they told us the compressor was bad - so we got a new one.

    The new/failed compressor was exactly two years from the sale-date so 'the failure' was 'found' on spring start-up two years ago. The customer says it worked all last year and was working at fall shutdown.

    PHM
    -------



    Quote Originally Posted by pecmsg View Post
    Please let us know if or when you find it.

    Any history on this system?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  10. #10
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    Hypothetically
    X-Valve floods the pump
    All oil is washed out
    Pump still running with No Oil
    Clunk before oil has a chance to return.
    Adapt to the valve outlet ( hope it’s flair) and blow N2.

  11. #11
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    Newest news -

    Blew out evap with 350 lb. nitrogen pressure - not a drop.
    Blew out cond. with 350 lb. nitrogen pressure - not a drop.

    I was deeply skeptical of the oil-logged-somewhere idea because the lines at the compressor change-out were bone dry. And the gauge-up was oil free. Typically an oil-pumper system has oil dripping out of everything. But I blew it all out anyway - nothing.

    I forgot to change the oil before installing the new compressor so I just added 2 ounces of POE to the AB oil in the new compressor. It's an R-12 compressor, previously charge smelled like R-409, I charged with R-134. Left the 1970's era R-12 TXV. SSH was 16º at the compressor - but the box started-up at a 90º box-temp and was only down to 69º when I called it A Day.

    BTW: I found a bodge that I have never seen before or thought of myself. The horizontal suction line leaving the evaporator was too short - between the coupling and the 90º ell to the riser - to allow mounting the TXV bulb. So someone had artfully mashed a piece of 3/8" copper flat and fit it exactly between the bells of the two fittings. The center was pinched together lengthwise so the recesses 'cradled' both the suction line and the bulb. The doubled thickness of the 'adapter' raised the ends of the TXV bulb enough to clear the bells. Pretty clever, in it's way, I thought. <g>


    I imagine that 'the adapter' would slightly delay the bulb response but probably not enough to matter under good insulation. Which this installation no longer had. <g>

    And of course it was all badly plated with that chalky crap which builds up under loose insulation - the line, the adapter, and the bulb. I cleaned it shiny but couldn't find heat paste in my 'rat's nest these days' truck so I used No-Ox to remounted the clean bulb onto the clean suction line. I abandoned the 'adapter' and mounted the bulb on the riser above the first 90. With the reasoning that I would prefer the vertical-to-horizontal mounting compromise over the 'more sh!t to go bad' inherent in the 'bulb-adapter' compromise.

    And I have never found any measurable difference in the bulb mounting position on suction lines 1 1/8" or smaller anyway. I really suspect that the bulb position mandate is a left over from the days when compressors sometimes produced greater oil carry-over. Modern compressors / systems in good condition seem to carry-over very little oil.

    I haven't been back yet (the UPS girl brought some toys <g>) but the customer, who is a delightful blond girl with a great smile and laughing eyes, told me the box is happily controlling at 35º F. this morning.

    No maintenance / repair records available so . . . . where did 20 ounces of oil go? remains a mystery.

    PHM
    --------


    Quote Originally Posted by pecmsg View Post
    Hypothetically
    X-Valve floods the pump
    All oil is washed out
    Pump still running with No Oil
    Clunk before oil has a chance to return.
    Adapt to the valve outlet ( hope it’s flair) and blow N2.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  12. Likes pecmsg liked this post
  13. #12
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    Short from the git go...

  14. #13
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    Perhaps it was your predecessor's experiment to develop an oil-less compressor?

    At this point I think I'd be cutting the old compressor open...or at least drilling a hole in the sump.

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