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  1. #1

    rack oil separator isolation porcedure

    Dear fellows:
    I need to pull open an oil separator located in the discharge line of a supermarket rack system to check the mesh screen and buoy mechanism. In order to isolate the separator, upstream I can shut all of the compressor´s discharge service valves. But downstream the separator there is no service shut-off valve but rather a differential discharge pressure regulator. It´s my understanding that this regulator, when energized, remains 100% open. When de-energized, it begins to close but never to a full shut-off. Is it possible to somehow completely close this regulator when the system is off, in order to isolate the separator from the condenser inlet? Thank you.

  2. #2
    Join Date
    Mar 2008
    Location
    North Queensland, Australia
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    1,051
    I'm a little confused. could you draw a diagram in MSpaint or some such and post it?
    Last edited by Slatts; 07-07-2008 at 03:24 AM.
    Mistakes are a part of being human. Appreciate your mistakes for what they are: precious life lessons that can only be learned the hard way. Unless it's a fatal mistake, which, at least, others can learn from. Al Franken, "Oh, the Things I Know", 2002

  3. #3
    Join Date
    Jan 2008
    Location
    NE FLA
    Posts
    64
    Check the condensers outside, most reliable installers will have ball valves for isolating different coils. .04c

  4. #4
    Join Date
    Jul 2005
    Location
    FLORIDA
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    1,163
    there should be ball valves to isolate the system so you can pull it apart to clean some where

    i have never seen a rack with out them

    there sould be one on the dicharge line just after the ddr and one going to suction lines for hot gas defrost
    once you think you've seen it all
    (THINK AGAIN)
    I would rather work for free than be look upon as a thief!!!!!

  5. #5
    Join Date
    Jul 2000
    Location
    Guayaquil EC
    Posts
    10,459

    Rack Isolation Valves....

    Isolation shutoff valves are optional on most rack systems, so I've seen a lot of them without valves. I've got one rack now with no high side valves at all between the compressor discharge and the receiver inlet.

    When I worked for a chain in Connecticut (years ago) we specified that all remote components like the condenser, reclaim coils, etc have isolation ball valves. That worked fine until one day on a walk-through an installer's fitter pointed out to one of the "Suits" how expensive these valves were.

    This Suit, or "glorified bagboy"...ie, Vice President...subsequently sent my boss a memo stating how much money we could save on installations.

    ....and so it goes.

  6. #6
    Join Date
    Jul 2005
    Location
    Southern California
    Posts
    590
    your boss should have sent a memo back about how much longer and more expensive any repair would take without the ball valves

  7. #7
    Join Date
    Jul 2000
    Location
    Guayaquil EC
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    10,459
    Quote Originally Posted by pherman View Post
    your boss should have sent a memo back about how much longer and more expensive any repair would take without the ball valves
    I sent a memo to that effect to my boss, the Director of Construction & Engineering. I think he just wiped his butt with it.

    He didn't care about such things because Store Maintenance was under someone else's budget.

  8. #8
    Join Date
    Sep 2005
    Location
    florida
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    5,514
    Quote Originally Posted by icemeister View Post
    Isolation shutoff valves are optional on most rack systems, so I've seen a lot of them without valves. I've got one rack now with no high side valves at all between the compressor discharge and the receiver inlet.

    When I worked for a chain in Connecticut (years ago) we specified that all remote components like the condenser, reclaim coils, etc have isolation ball valves. That worked fine until one day on a walk-through an installer's fitter pointed out to one of the "Suits" how expensive these valves were.

    This Suit, or "glorified bagboy"...ie, Vice President...subsequently sent my boss a memo stating how much money we could save on installations.

    ....and so it goes.
    All my rackrs have isolation valves high side and low but some still leak by
    making it a fun day.
    I love the smell of phosgene first thing in the morning:

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  9. #9
    Quote Originally Posted by coldkeeper1 View Post
    Is it possible to somehow completely close this regulator when the system is off, in order to isolate the separator from the condenser inlet? Thank you.
    NO
    Don't interrupt me while i'm talking to myself

  10. #10
    Hi again.
    I´ve been looking for any kind of hidden islolation valve but there is none. What I´ve got here is a very long pipe run from my separator, through the discharge differential pressure regulator up to the remote condenser inlet valve. I guess I´m going to have to shut all the compressors´discharge service valves, do the same with the condenser inlet valve, recover the refrigerant left in the piping between these two points and then pull apart the separator. Same procedure if someday the DDPR fails. All of this because the installer/manufacturer couldn´t afford to put an insolation valve right after the DDPR.
    For SLATS: just to clarify, the piping goes like this: compressors´discharge service valves, common discharge manifold, helical oil separator, discharge differential pressure regulator, long pipe run, remote condenser inlet valve. Thank you all for your interest and comments.

  11. #11
    Join Date
    Mar 2008
    Location
    North Queensland, Australia
    Posts
    1,051
    I'm trying to start a revolution. Some of the explanations in the forums are so convoluted I get a head ache just reading them.
    a couple of minutes with a graphics program could save half a dozen posts.
    Doesn't have to be a master piece, just clear and labelled.
    Attached Images Attached Images  
    Mistakes are a part of being human. Appreciate your mistakes for what they are: precious life lessons that can only be learned the hard way. Unless it's a fatal mistake, which, at least, others can learn from. Al Franken, "Oh, the Things I Know", 2002

  12. #12
    Join Date
    Mar 2008
    Posts
    257
    Quote Originally Posted by coldkeeper1 View Post
    Hi again.
    I´ve been looking for any kind of hidden islolation valve but there is none. What I´ve got here is a very long pipe run from my separator, through the discharge differential pressure regulator up to the remote condenser inlet valve. I guess I´m going to have to shut all the compressors´discharge service valves, do the same with the condenser inlet valve, recover the refrigerant left in the piping between these two points and then pull apart the separator. Same procedure if someday the DDPR fails. All of this because the installer/manufacturer couldn´t afford to put an insolation valve right after the DDPR.
    For SLATS: just to clarify, the piping goes like this: compressors´discharge service valves, common discharge manifold, helical oil separator, discharge differential pressure regulator, long pipe run, remote condenser inlet valve. Thank you all for your interest and comments.
    Sounds to me like you found it. Just a trick I use in these cases, before you start pump down a couple of your larger systems on the rack, 3-4 psig. Then shut the pumps off one at a time isolateing the discharge as you go. Finally shut the inlet to the condensor, and dump the remaining discharge gas back into the systems you pumped down when you started. I would have new float in hand because you don't need to repete this if there is a problem.

  13. #13
    Join Date
    Mar 2008
    Posts
    257
    Quote Originally Posted by gerryboy00 View Post
    NO
    I like this answer the best

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