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  1. #14
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    Right now I am battling with the front wheel bearing assemblies in my Florida Van (I just came inside to take a Tea Break - I don't feel like waiting for four today <g>) but I was just sitting on the box with the just-replaced compressor in it so I'll get to compressor shell drilling as soon as my massive sledgehammer work is successful.

    PHM
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    Quote Originally Posted by icemeister View Post
    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.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  2. #15
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    With me knowing nothing - I suppose a guess is as good as anything. <g>

    Maybe the installer dropped the compressor off the condensing unit sideways - or while removing it from the box - and the oil drained out. Or maybe the previous installer has mastered the fine art of dooming the compressor by low oil level just after the warranty period concludes?

    But now that I found out that it was my long time refrigeration friend who installed the previous compressor - I have to go with factory error as being the likeliest. John would never have installed a known-compromised compressor - not a Chance.

    That conclusion makes me even sorrier I didn't drain and re-fill the new compressor - at least that way I would have known that this new-new compressor held the correct oil charge. <g>

    PHM
    -------


    Quote Originally Posted by icemeister View Post
    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.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  3. #16
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    Oh Ice; that reminds me - I want to ask you for an opinion.

    Yours I mean. <g>

    This is a Bohn two fan evap unit - oh wait: I have the actual model number

    Bohn - ADT900A (that D could be an O)

    Evap is about 5' higher than the condensing unit. There is a 7/8" OD copper suction line run: out of the evap 6" - no trap - then a 15" riser - no reverse-trap - then 10' horizontal - then a 50" drop straight into the compressor's 5/8" suction service valve.

    In regard to mineral or alkylbenzene oil return with R-134 - Do you picture that this configuration and application would tolerate the non-solvent refrigerant? And I mean in the sense of still having adequate oil return?

    I added some POE (about 8-9%) because I forgot to change all the oil before installing the compressor - and I'd didn't want to pure-experiment as apparently this is the only available compressor in the eastern US. <g>

    I really have a problem picturing that simple turbulence / velocity wouldn't get the oil up a 15" riser and the rest of the travel is downhill. But what do you think?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  4. #17
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    Quote Originally Posted by Poodle Head Mikey View Post
    Oh Ice; that reminds me - I want to ask you for an opinion.

    Yours I mean. <g>

    This is a Bohn two fan evap unit - oh wait: I have the actual model number

    Bohn - ADT900A (that D could be an O)

    Evap is about 5' higher than the condensing unit. There is a 7/8" OD copper suction line run: out of the evap 6" - no trap - then a 15" riser - no reverse-trap - then 10' horizontal - then a 50" drop straight into the compressor's 5/8" suction service valve.

    In regard to mineral or alkylbenzene oil return with R-134 - Do you picture that this configuration and application would tolerate the non-solvent refrigerant? And I mean in the sense of still having adequate oil return?

    I added some POE (about 8-9%) because I forgot to change all the oil before installing the compressor - and I'd didn't want to pure-experiment as apparently this is the only available compressor in the eastern US. <g>

    I really have a problem picturing that simple turbulence / velocity wouldn't get the oil up a 15" riser and the rest of the travel is downhill. But what do you think?
    It's been my practice to follow Hussmann piping guidelines from many years past, which in regard to suction traps, a trap is required for any riser in excess of 4 feet. So I believe you're OK from that standpoint.

    Then there are those who will rant about the need for a trap at the outlet of the evaporator to prevent collected oil from affecting the TXV sensing bulb function. I'm not necessarily one of those, at least not a card carrying, pot banging member. I feel that these smaller units aren't really a problem without the evaporator trap.

    In fact, it doesn't need to be a trap at all....just provide a means of free draining for the oil leaving the evaporator and that is more than sufficient.

  5. #18
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    Thanks, but none of that is directed at my actual question.

    Which is:
    In regard to mineral or alkylbenzene (no POE added) oil-return with R-134 - Do you picture that this configuration and application would have adequate oil return?

    I vigorously used a hatchet and so got the RF wheel bearing assembly off my FL Van - which then allowed me to drill the bottom curve of the shell of the just removed compressor in question. When set upright over a drain pan - ZERO additional oil came out of the compressor. So that ain't where it's hiding. <g>

    PHM
    --------


    Quote Originally Posted by icemeister View Post
    It's been my practice to follow Hussmann piping guidelines from many years past, which in regard to suction traps, a trap is required for any riser in excess of 4 feet. So I believe you're OK from that standpoint.

    Then there are those who will rant about the need for a trap at the outlet of the evaporator to prevent collected oil from affecting the TXV sensing bulb function. I'm not necessarily one of those, at least not a card carrying, pot banging member. I feel that these smaller units aren't really a problem without the evaporator trap.

    In fact, it doesn't need to be a trap at all....just provide a means of free draining for the oil leaving the evaporator and that is more than sufficient.
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  6. #19
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    Quote Originally Posted by Poodle Head Mikey View Post
    Thanks, but none of that is directed at my actual question.

    Which is:
    In regard to mineral or alkylbenzene (no POE added) oil-return with R-134 - Do you picture that this configuration and application would have adequate oil return?

    I vigorously used a hatchet and so got the RF wheel bearing assembly off my FL Van - which then allowed me to drill the bottom curve of the shell of the just removed compressor in question. When set upright over a drain pan - ZERO additional oil came out of the compressor. So that ain't where it's hiding. <g>

    PHM
    --------
    I would be concerned about the oil return up the riser without the added POE. It would probably return, but would leave a higher than normal concentration of oil stuck in the evaporator I would think.

    It also would be a good candidate for your Supco 88 additive, no?

  7. #20
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    Yes; but I have become intrigued by some fairly recent refrigeration research showing that adding POE produces superior oil return as compared to adding hydrocarbons.

    PHM
    -------


    Quote Originally Posted by icemeister View Post
    I would be concerned about the oil return up the riser without the added POE. It would probably return, but would leave a higher than normal concentration of oil stuck in the evaporator I would think.

    It also would be a good candidate for your Supco 88 additive, no?
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

  8. #21
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    That reminds me of a somewhat funny story in regard to this job site.

    After I got lured there by the easy 'walkin is running a little warm' lie I was subsequently told that a number of freezers were not working.

    This bad-compressor walkin we have been talking about had/has an R-12 compressor. I have most of an ancient 50 pounder of R-12 sitting in the shop. So I thought: I'll get rid of that now useless crap by just charging this system with R-12. <g>

    So I grab the cylinder but at the job site I discover that the white cylinder actually contains R-502. Back when disposable cylinders did not have a check valve and could be refilled a former partner of mine charged 40-50 lbs. of R-502 into an new R-12 rack. After I screamed he pumped it back out into whatever cylinder that was handy - this R-12 can. <g>

    All these years later I had forgotten all about that incident. <g>

    So I was pissed off after finding my clever R-12 efforts were thwarted - but then I discovered that one of the old, now down, freezer walk-in systems was originally R-502. At one point it apparently had R-408 in it and then later R-422. I found it with all the seal caps missing, 30 lbs. static, and missing about 25 lbs of charge volume. <g> I would have charged it with R-407A but using the R-502 cheered me for some reason. I guess the absurd coincidence of it all. <g>

    This made me unpissed off as I could now use the "R-12 which turned out to be R-502" to charge this old freezer with it's original refrigerant. And boy did that make it happy! <g>
    PHM
    --------
    The conventional view serves to protect us from the painful job of thinking.

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