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  1. #1
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Hi all.

    I will admit in the past that I haven't always ran nitrogen through my refrigerant lines while brazing. But this spring and summer I want to be very meticulous in doing so. The main reason I want to do this is because of the new company I now work for. From what I have heard and from questions I have asked I know that no one here does it. Not only that, they don't use micron gauges while pulling a vacuum on their systems. They said that they installed around 200 AC's/Heat pumps last year and I am just wondering how many of these systems are going to have potential problems because they didn't do either. I'm gonna make sure everyone is doing it by this spring and I don't care what my boss tells me to do. Just a few weeks ago I had to teach them that you must use primer when putting together PVC. Sure there are other things I will find, but this is it so far. My question is, on the method of flowing nitrogen while brazing. Do I need to hook the lines up to the OD unit first, so I can use the service ports as taps to introduce nitrogen to the system or is there an easier way so I can have it flowing from the beginning? Sorry, if this is a stupid question but it shows you how many people I know that don't do it, and I've been doing this for 11 years.

  2. #2
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Just lay out all of your piping, take out the schrader valves(both), then hook up to opposite side you're starting on, flow small amount(3psig), should feel it out of other service port, then take off brazing.
    If everything was always done "by the book"....the book would never change.

  3. #3
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Thanks smokin, I thought of that but was thinking wouldn't get a good flow without one solid connection. Guess I'm wrong.

  4. #4
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Get all your piping in place and ready for brazing. Take the valve cores out and purge all the air out of the lines with nitrogen at ~25 psi through the liquid side.
    Once all the air is purged out with nitrogen, you need just barely enough nitrogen flow to have a slight positive pressure coming out of the oposite port.
    Usually my gauge is barely reading 1 psig when I'm flowing nitrogen while brazing.

    Ideally you could use a regulator with a flow gauge to insure you have a positive flow into the lines.
    If more government is the answer, then it's a really stupid question.

  5. #5
    Join Date
    Sep 2005
    Posts
    685
    Notrogen is ok if you have the time I guess.

  6. #6
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Originally posted by curry
    Notrogen is ok if you have the time I guess.
    I don't have the time/patience to have to go back and do it again or clean out a md screen. Much easier to hook up the nitro...
    If everything was always done "by the book"....the book would never change.

  7. #7
    Join Date
    Jul 2001
    Location
    Central MN and the Twin Cities
    Posts
    1,530
    I have always done much like Mark. It takes a little extra time at first, but once it is habitual its mere seconds. Well worth never having a callback. Most everyplace I have worked they would have everything there to pressure test with nitro so why not flow it? Everything is right there.
    Warning: Just because I am over the head injury doesn't mean I'm normal!

    The day I stop learning.... I'm dead!

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