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  1. #1
    Join Date
    Apr 2007
    Location
    Clearwater, FL
    Posts
    4

    Flush New Line sets with R-11 instead of flowing Nitrogen?

    I'm planning to have two new R-410A systems installed to replace some old R-22 equipment. So far the various contractors have agreed that new line sets are in order. That's fine with me - that's what I want.

    I asked the most recent fellow (established contractor/owner) if he'd flow nitrogen while brazing the new line sets and he confidently said, "No, he would not." He says he has a better method. What is it? After brazing he likes to run an R-11 flush through the lines - he claims it does a much better job and even suggested that flowing nitrogen was an outdated method. He talked a few minutes more about how expensive this little container of R-11 was and how it didn't make sense that it was still available what with all the environmental concerns surrounding R-22 and all. Puzzling indeed...

    I didn't know what to think other than something didn't sound right. So after some reading today I learned that due to EPA regulations the real R-11 is no longer supposed to be available. So I figure maybe he really meant he's using the Rx-11 Flush substitute or something like it. Who knows....

    But regardless of what he might be using as a flush, my real question is this:

    Does it make sense when brazing a new line set to skip flowing nitrogen in favor of some follow-up R-11 type flush? Is this in any way preferable, superior to, or a substitute for flowing nitrogen while brazing? Wouldn't this method just run the risk of introducing other contaminants into an otherwise clean line set?

    I know a flush makes sense for burnouts or when re-using lines for r410 that were previously charged with r22, but on new lines? Any thoughts on this new twist to the nitrogen flow / line set replacement debate is appreciated?

  2. #2
    Join Date
    Jun 2003
    Location
    Hell Hole Swamp
    Posts
    4,180
    Lets see...

    prevent oxides from forming in the first place, or let them form and then attempt to flush them out with something after the fact.

    what sounds like the better option?

    nevermind the flush is much more expensive than nitrogen, literally an ounce of prevention is worth a pound af cure in this case.

  3. #3
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    We don't flush new linesets. Braze em up and dry nitro pressure test. Triple Evac and your all set ready to go.

    Systems now-a-days have filter dryers to remove contaminants from the system. So a flush is IMO an un-neccessary step. But if the contractor wants to spend extra money, make sure its not out of your pocket.

  4. #4
    Join Date
    Jul 2006
    Location
    NW burbs of Detroit
    Posts
    6,058
    nitrogen is ok to use.. But if your brazer is good at what he does (ie; FORMIN THE BRAZE WITH OUT over heating the copper thus accounting for little to no scale) then nitro really is not a necessity as a generously sized LL filter drier will pick up any small traces tha could have formed.
    I can oly speak for my self so if you are using somebody fror the first time you should expect a nitro flow.

  5. #5
    Join Date
    Feb 2007
    Posts
    999
    Quote Originally Posted by hvaclover View Post
    ..... a generously sized LL filter drier will pick up any small traces tha could have formed.
    If the filter/drier is in the condensing unit, what happens to any scale formed at the braze of tubing (LL) to evaporator?


    AM

  6. #6
    Join Date
    Jul 2006
    Location
    NW burbs of Detroit
    Posts
    6,058
    Quote Originally Posted by ampulman View Post
    If the filter/drier is in the condensing unit, what happens to any scale formed at the braze of tubing (LL) to evaporator?


    AM
    I put the filter drier at the evap inlet. And there is also a screen in the TXV in let also.

  7. #7
    Join Date
    Dec 2007
    Location
    Ohio
    Posts
    2,876
    Quote Originally Posted by hairy View Post
    I asked the most recent fellow (established contractor/owner) if he'd flow nitrogen while brazing the new line sets and he confidently said, "No, he would not." He says he has a better method. What is it? After brazing he likes to run an R-11 flush through the lines - he claims it does a much better job and even suggested that flowing nitrogen was an outdated method. He talked a few minutes more about how expensive this little container of R-11 was and how it didn't make sense that it was still available what with all the environmental concerns surrounding R-22 and all. Puzzling indeed...

    Sounds to me like this guy is trying to impress you with his "knowledge". Fact of the matter is there is no better way to braze linesets than with a nitrogen purge. I do understand (as stated above) that if you don't heat the joint hot enough then you have nothing to worry about....however can you trust someone to do that every time??? It takes years of experience to be that good with brazing and besides that what temperature is too hot and how do you measure it? 410 systems need to be brazed with a nitrogen purge or soldered with stay brite #8...then evacuated to at least 400 microns THREE times, breaking each with a pound or two of nitrogen. There would never be any kind of reason to run that Rx-11 flush through a brand new lineset....if this is being added to the cost of your install....IMO it's nothing you should have to pay for....sounds to me like he is using it to try and show some kind of value...when in fact it just plain unnecessary.
    I need a new signature.....

  8. #8
    Join Date
    Jul 2001
    Location
    VA
    Posts
    2,801
    Ummmmm.... the guy is a retard........ I'd get someone else.

    Its like saying that its good to smoke as long as you have a good heart surgeon.
    ___________________________________________


  9. #9
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,189
    Quote Originally Posted by hvaclover View Post
    nitrogen is ok to use.. But if your brazer is good at what he does (ie; FORMIN THE BRAZE WITH OUT over heating the copper thus accounting for little to no scale) then nitro really is not a necessity as a generously sized LL filter drier will pick up any small traces tha could have formed.
    I can oly speak for my self so if you are using somebody fror the first time you should expect a nitro flow.
    Bull poop
    Perhaps you should have read the instructions before calling.

  10. #10
    Join Date
    Dec 2007
    Location
    Ohio
    Posts
    2,876
    Quote Originally Posted by jrbenny View Post
    Bull poop

    Thanks...I now have pop running out of my nose and onto my keyboard
    I need a new signature.....

  11. #11
    Join Date
    Jul 2001
    Location
    VA
    Posts
    2,801
    Quote Originally Posted by hvaclover View Post
    And there is also a screen in the TXV in let also.
    That would be the one that will clog with the black stuff when you are leaving the job if you didnt nitro-flow.
    ___________________________________________


  12. #12
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,100
    So how does the filter catch the oxidation on its outlet side. Its after the filter.
    There are many excuses for not using nitrogen.




    To the OP:
    I'm sure he meant RX11 flush. It works great, and should have notrogen used to blow it out of the line set.
    So that contractor is kind of off target at having any great advantage over not flowing nitrogen while braziing.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  13. #13
    Join Date
    Jul 2006
    Location
    NW burbs of Detroit
    Posts
    6,058
    Quote Originally Posted by beenthere View Post
    So how does the filter catch the oxidation on its outlet side. Its after the filter.
    There are many excuses for not using nitrogen.




    ng.
    Yeah there is! The tank is really heavy.

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