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  1. #27
    Join Date
    Jun 2003
    Location
    Chicago, IL
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    4,361
    Quote Originally Posted by beenthere View Post
    Your basing your saturation on all the refrigerant being in only X part of the system, if it only has X amount left in it.

    Even if it only has 3 pounds in it. There will be some liquid in the condenser, and the line set.
    Depends how long it sits. After a its off long enough all the refrigerant liquid will be in the coldest part of the system as long as theres room to accept it. If theres not room it moves to the next coldest part.

    Thats why if you work on refrigeration you get calls for warm freezers when its 20 below outside. If theres not more refrigerant in the system than the condenser can hold, all the refrigerant will migrate to the condenser during the off cycle, and take on a pressure that corresponds to the outdoor temperature. When the solinoid opens on a call for cooling, the refrigerant will just sit there because it has no incentive to move to a warmer place (the freezer at 0 degrees). The compressor won't start because the pressure in the system is lower than the cut in point on the compressor. There needs to be enough refrigerant in the system so that there is always some in the indoor receiver or outdoor heated reciever if long off cycles are expected.

  2. #28
    Join Date
    Nov 2001
    Location
    Seattle, WA
    Posts
    7,751
    Quote Originally Posted by ICanHas View Post
    Is it a crime to ask questions without stating the purpose of necessity?
    Actually, yes. The HVAC-talk wrong question cops will be by shortly.

    There usually is a question behind these types of questions and that is what I'm interested in. It's an educational process. You asked about the sitting pressure inside a sealed system and I'm interested in what you are attempting to attempt.

    Maybe there is a better way for you to find out what you are looking for. Or maybe you are on to a new science that all of us could benefit by.

    By your defensive stance, I'm assuming you don't want to expose yourself to deeper questioning.
    "The American Republic will endure until the day Congress discovers it can bribe the public with the public's own money.
    - Alexis de Toqueville, 1835

  3. #29
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    17,952
    Quote Originally Posted by beenthere View Post
    Static pressure is mentioned in water systems/piping/plumbing, air planes, and many other things.

    Static pressure, is simply the pressure exerted by something in all directions.

    I like the give and take with you on these points.

    Okay.

    All of the things you mentioned do indeed have specific ideas assoociated with "static pressure."

    In fact, that is pretty much what I was pointing out.

    HVAC has a specific expectation for the words, "static pressure."

    RSES Journal has an article on leak prevention in systems, and there are four of five mentions of "standing pressure," in regards to the ability of the system to hold pressure during leak testing.

    http://www.rses.org/assets/rses_journal/0710_Leak.pdf

    And it is referenced here http://hvac-talk.com/vbb/showthread.php?t=251392 in the same vein.

    ..and my application of the term is used in this HVAC textbook, on page 563:

    http://books.google.com/books?id=gni...anding&f=false
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

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  4. #30
    Join Date
    Aug 2010
    Posts
    2,486
    Quote Originally Posted by timebuilder View Post

    RSES Journal has an article on leak prevention in systems, and there are four of five mentions of "standing pressure," in regards to the ability of the system to hold pressure during leak testing.
    Though I was asking for the purpose of determining maximum tolerable pressure for testing, what I was asking is the steady state refrigerant loop pressure when it is not running.

  5. #31
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    67,778
    Quote Originally Posted by ICanHas View Post
    Though I was asking for the purpose of determining maximum tolerable pressure for testing, .
    What ever the test pressure is of the indoor coil.
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  6. #32
    Join Date
    Aug 2010
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    2,486
    I suppose that means not less than 250 psi, unless the indoor coil will rupture if the ambient gets to 110F.

  7. #33
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    Jan 2004
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    Lancaster PA
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    Quote Originally Posted by ICanHas View Post
    I suppose that means not less than 250 psi, unless the indoor coil will rupture if the ambient gets to 110F.
    No. Just means that is a safe pressure to use for leak testing. Can use less if you want.
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  8. #34
    Join Date
    Aug 2010
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    Quote Originally Posted by beenthere View Post
    No. Just means that is a safe pressure to use for leak testing. Can use less if you want.
    I meant safe pressure is not less than 250psi. The more pressure you use, the easier it is to find small leaks, isn't it?

  9. #35
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    Jan 2004
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    Lancaster PA
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    Quote Originally Posted by ICanHas View Post
    I meant safe pressure is not less than 250psi. The more pressure you use, the easier it is to find small leaks, isn't it?
    Generally yes.
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