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  1. #1
    Join Date
    Jun 2008
    Posts
    4

    Standing Pressure Test

    Refrigeration and Air Conditioning Technology by Whitman instructs you to perform a standing pressure test by filling a new system with dry nitrogen up to the operating pressure of the system. It does not instruct you to pull a vacuum first before introducing the nitrogen.

    Do you first pull a vacuum to remove any moisture or non-condensables?

  2. #2
    Join Date
    Dec 2005
    Posts
    3,931
    Pull the vacuum after the leak test.

    Also if you're just testing the your field welds, bubbles and or a good sniffer is you're best bet.

  3. #3
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    Quote Originally Posted by mls228 View Post
    Refrigeration and Air Conditioning Technology by Whitman instructs you to perform a standing pressure test by filling a new system with dry nitrogen up to the operating pressure of the system. It does not instruct you to pull a vacuum first before introducing the nitrogen.

    Do you first pull a vacuum to remove any moisture or non-condensables?
    You should already be flowing n2 while your brazing, right?
    Karst means cave. So, I search for caves.

  4. #4
    Join Date
    Jun 2008
    Posts
    4
    Quote Originally Posted by karsthuntr View Post
    You should already be flowing n2 while your brazing, right?
    Yes, absolutely.

  5. #5
    Join Date
    Jun 2004
    Location
    Location:Raleigh NC
    Posts
    9,601
    standing pressure test
    then Tripple evac.
    If you help others then you are a Success

  6. #6
    Join Date
    Jul 2001
    Posts
    3,112
    Standing pressure test to check for leaks. If no leaks, blow nitrogen, evacuate and charge system. If there is a leak, repair it, pressure check again with nitrogen, then follow procedures. If you have a leak in a system, why would you try and pull a vacuum first and run the chance of drawing air, moisture etc into the system? Find the leaks, fix them then do you evacuation and charge.

  7. #7
    Join Date
    Jul 2006
    Location
    Anytown USA
    Posts
    2,055
    i usually dump a little refrigerant in the system then pump it up with nitro to 200-250psi. go around with the leak detector , if no leaks dump that nitro, pull a vacuum and charge.

    I never pull a vacuum on a known leaking system. In my thinking, a new system is a leaking system until you prove it isnt.

  8. #8
    Join Date
    Mar 2009
    Location
    Colonie, NY
    Posts
    23
    on an install if u time it right pressure testing is just in time for lunch. ramp up the nitrogen to 200psig then go get lunch if its still 200 when u get bck dump that evacuate and charge.

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