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  1. #1
    Join Date
    Jul 2008
    Posts
    4

    Trane scroll compressor

    Hi,Guys

    Came across a trane watersource a/c unit model# (5cwgn304f)found 15 ton scroll compressor wired backwards.Switched leeds and now the unit goes right in to a vacuum found liquard line full of oil has any one seen this and what did you do to fix??

  2. #2
    Join Date
    Oct 2002
    Location
    Lexington, NC
    Posts
    5,122
    unit goes into a vacuum on what? The suction line? Are you sure that the service valves are open? No selonoids closed somewhere you aren't seeing?
    How are you sure it was running backwards before? How long has it supposedly been running backwards?

  3. #3
    Join Date
    Jul 2008
    Posts
    4
    There are no service valves or soilenoids on this unit.Not sure how long it has been running or ran at all with the rotation backwards.

  4. #4
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    what was the head pressure when the suction went into a vacuum

    ohh by the way, dont let scrolls run in a vacuum!



    .

  5. #5
    Join Date
    Jul 2008
    Posts
    4
    Head presure goes up just a little to 150psi

  6. #6
    Join Date
    Nov 2003
    Location
    Boston
    Posts
    600
    llsv
    Edited by powerhead on more than one occasion

  7. #7
    Join Date
    Jul 2008
    Posts
    4
    Does not have one

  8. #8
    Join Date
    Oct 2001
    Posts
    6,855
    cap tube is snapped off the TXV power head,LL is blocked with oil and the element has broke down within it to make the vac
    "when in doubt...jump it out" http://www.youtube.com/watch?v=Px5YcOeQB4I

  9. #9
    Join Date
    Oct 2002
    Location
    Lexington, NC
    Posts
    5,122
    first, check you gauge. Put the highside on the suction port just to make sure. Have you put any freon in to see what will happen? If you are pumping down due to a restriciton, then you will build your head pressure. I changed a compressor out one time and it immediately pumped down like you are describing. I figured out that there was a strainer screen in the line that had clogged up with burnt oil. You have this same problem with a strainer or check valve or line dryer. You may have to open the system and pump some nitrogen in to locate the problem. If you are pumping in and nothing is coming out, you have a restriction. I am fairly confident that this is your problem. You probably already have a low charge anyway according to what you are saying. Let us know what you find. No one here will be able to help you until you verify with nitrogen or some other way that you are not pumping down due to a restriction in the system.

  10. #10
    Join Date
    Oct 2002
    Location
    Lexington, NC
    Posts
    5,122
    To make it more simple, this is what I am talking about. You have pressures on both sides. You turn compressor on and the suction goes to a vacuum and the head pressure raises a little. No more freon is going in to the condensor and what is in there is cooling. therefore, the head does not rise, and may even fall a little. When the freon comes out of the condensor, it is being blocked before it makes it to the metering device by a line dryer or strainer, something totally blocking the metering device orifice including one of those TXV's that close all of the way, or something else in the circuit. Remember that when you shut down a scroll, the pressures equalize because there are no valves. This is why the pressures prbably go back to equal at shut down.
    Again, check it out and let us know. Please not that if the restriction is 100 percent, you will not be able to check it by way of a temperature drop because there is no metering type action taking place.

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