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  1. #1
    Join Date
    Sep 2005
    Location
    Texas
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    2,793
    I have a mid temp box with a coplamatic semi that is 2 floors below the evap coil. Looked at the crankcase sight glass and no oil visible. It is R22. Could the oil have migrated all the way up to the evap coil? Dont want to overfill it.

  2. #2
    Join Date
    May 2004
    Posts
    11,999

  3. #3
    Join Date
    Jul 2000
    Location
    Guayaquil EC
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    10,328

    Give us a little background info.........

    Is this system one that's been in service for a long time or a new installation?

    Any previous oil-related problems?

    What was the nature of the service call and what else beside low oil did you find.......low refrigerant and short-cycling maybe?

    As Lusker suggested, check your system piping for possible oil trapping in the suction line routing or piping itself. Look for obvious oil leaks around the system. You also can have significant oil leaks with little refrigerant loss in some cases.

    Check the condition of the compressor. It may be pumping oil due to internal mechanical problems like wear, broken/stuck rings, etc.

  4. #4
    Join Date
    May 2004
    Posts
    11,999
    IM

    I emailed him a link to the Hcraft install/opps manual. Thats why my above post was edited.. i removed the link and sent it to him

    He should check out the pipping install techniques and match them to his install before adding oil

    ya think?


  5. #5
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,328
    The Heatcraft I&O is indeed a good reference for the typical commercial refrigeration system in general. Their piping section is very good.

    A little investigating is definitely in order before adding oil, but under some circumstances I would opt to add the oil just to get the system back on line and the customer back in business whilst I check things out. Often the answer may appear straightaway if the oil you added rapidly disappears from sight.

    Another excellent piping manual is DuPont's Refrigerant Piping Handbook.

  6. #6
    Join Date
    Nov 2005
    Posts
    28
    hey icemeister you brought up a point ive been curious about. How is it possible to have oil loss without refrigerant loss? I know oil doesnt change state like refrigerant does if you have a leak and you have a gas and oil mixture the oil leakx out faster than the gas. Is right?

  7. #7
    Join Date
    Sep 2005
    Location
    Texas
    Posts
    2,793

    Duponts

    piping handbook is user friendly

  8. #8
    Join Date
    Nov 2000
    Location
    Coastal Georgia
    Posts
    34,902
    I had a 5 horse pumping the oil out on low load conditions and would trip the OPC on pump down.

  9. #9
    Join Date
    Sep 2005
    Location
    Texas
    Posts
    2,793

    how did you

    correct that issue?

  10. #10
    Join Date
    Nov 2000
    Location
    Coastal Georgia
    Posts
    34,902
    Ajusted the cut out on the DP to cut out sooner and tweaked the expansion valve open as I recall.

    [Edited by JAMES 3528 on 02-07-2006 at 12:16 PM]

  11. #11
    Join Date
    Oct 2004
    Posts
    3,400
    Originally posted by ice cuber
    hey icemeister you brought up a point ive been curious about. How is it possible to have oil loss without refrigerant loss? I know oil doesnt change state like refrigerant does if you have a leak and you have a gas and oil mixture the oil leakx out faster than the gas. Is right?
    Likely, the oil didn't leak out.

    It simply migrated to a different part of the system.

    Improper piping can cause this movement.

  12. #12
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,328

    Oil Leaks.......

    What I was referring to back then was about a scene I've noticed many times where there is an obvious leak where oil is all over......like saturated Armaflex and a big smear on the floor and yet the refrigerant leakage is barely detectable. It's usually where there is a small pinhole in a joint and the oil partially seals against the refrigerant pressure. I also see it on tin can hermetics where the base of the compressor has severely rusted.....lots of oil but little gas lost.

    So just because there's no apparent refrigerant loss in the system, over time there may in fact have been significant oil loss.

  13. #13
    Join Date
    Sep 2005
    Location
    Texas
    Posts
    2,793

    is there a method

    to get what oil is in the system back to the sump as to be able to tell what the true level is?

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