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  1. #1
    Join Date
    Mar 2005
    Posts
    65
    Old lady's system next door apparently still has her system charged with nitrogen.psig's on both sides equeal at 150 with system running.First thought was bad valves until I found system was full of nitrogen.Does anyone know if a compressor with cap tupe metering device will condense nitrogen enough to get low and high pressure readings?I don't want to waste the effort if her valves are shot.Doin it for free, so any help is appreciated.

  2. #2
    Join Date
    Nov 2001
    Posts
    1,874
    I don't believe I've ever heard of nitrogen being able to change state,
    It's an inert gas.
    If you try to fail, and succeed.
    Which have you done ?



  3. #3
    Join Date
    Sep 2002
    Location
    South Dakota
    Posts
    6,579
    Originally posted by Toolpusher
    I don't believe I've ever heard of nitrogen being able to change state,
    It's an inert gas.

    Any gas can be liquified given enough pressure. Nitrogen will not condense in an air conditioning or refrigeration system. The system operates at pressures far below the condensing temperature-pressure (saturation) of nitrogen.


  4. #4
    Join Date
    Oct 2001
    Location
    Waterford Michigan
    Posts
    2,668
    Now how would the system get full of nitrogen?

  5. #5
    Join Date
    Nov 2001
    Posts
    1,874
    sorry I'll go back to my cornor now
    If you try to fail, and succeed.
    Which have you done ?



  6. #6
    Join Date
    Sep 2002
    Location
    South Dakota
    Posts
    6,579
    Originally posted by johnl45
    Now how would the system get full of nitrogen?

    1. If the system is full of air it already contains 78% nitrogen.

    2. Nitrogen is often put in systems for purging during brazing at the time of installation and is also used for leak testing. All real technicians carry nitrogen with them.


  7. #7
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,517
    no
    remove the nitrogen
    evacuate the syatem and wiegh in the proper charge
    look at the name plate and find out what kind of refrigerant is being used
    if you run it with nitrogen you will blow the compressor

  8. #8
    grodan1

    I can’t believe anyone would leave nitrogen in the system, without locking out the compressor circuit. How did you determine its nitrogen in the system?

    With equal pressures hi and low with compressor actually running, would indicate a defective compressor, or if a heat pump maybe the reversing valve.
    (are you sure the compressor was running and not just the fan operating)

  9. #9
    Join Date
    Jun 2002
    Location
    Bemidji, Mn
    Posts
    3,573
    Coulda been worse and said oxygen!
    You picked a fine time to leave me loose wheel...

    http://rapalaguy.spaces.live.com/

  10. #10
    Join Date
    Mar 2005
    Posts
    65
    How did I determine it had nitrogen in it? I remembered what happened at school when students took their hoses off without first bleeding the liquid refrigerent in their red hose into the low system so only vapor was in hose.When that happened a bunch of liquid refrigerent came shooting out.So I purposely took my hoses off wrong in the way to make sure my red hose would still be full of liquid.When I opened it (slowly,so I could shut it off if it was refrig)my presssure went from 130 to nothing and it sounded weak as a pop-corn fart.Plus the old lady said "they"said they would return and put refrigerent in her system when they returned, but they never did.

  11. #11
    Join Date
    Oct 2001
    Location
    Waterford Michigan
    Posts
    2,668
    Originally posted by NormChris
    Originally posted by johnl45
    Now how would the system get full of nitrogen?

    1. If the system is full of air it already contains 78% nitrogen.

    2. Nitrogen is often put in systems for purging during brazing at the time of installation and is also used for leak testing. All real technicians carry nitrogen with them.

    Where I'm from here we call air, air and nitrogen, nitrogen. All real technicians know this regardless if they carry nitrogen or some other inert gas.

  12. #12
    Join Date
    Oct 2004
    Posts
    3,400
    Originally posted by Toolpusher
    I don't believe I've ever heard of nitrogen being able to change state,
    It's an inert gas.
    There are only six inert gases:
    helium, neon, argon, krypton, xenon, and radon.

    Nitrogen is not inert.

    Anything and everything will change state, with enough temperature and/or pressure change.

    That being said, nitrogen is one of the things we refrigeration people call "non-condensables".

    That just means it won't change state at the temperatures and pressures found in your normal, run-of-the-mill, air conditioner. (so you were right.)

    (You have heard of liquid nitrogen, right? Same stuff. Doctors use it to freeze warts.)





  13. #13
    Join Date
    Apr 2004
    Location
    Niantic, Illinois
    Posts
    545
    Originally posted by grodan1
    Plus the old lady said "they"said they would return and put refrigerent in her system when they returned, but they never did.
    Has she tried contacting them. If she hasn't even tried then how does she know whether they are willing to take care of her or not? Don't just assume they will not. Someties people fall through the cracks by accident.It's happened to all of us.

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