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converting to 410a

Paul_69
Paul_69 Member Posts: 251
in A-C, Heat Pumps & Refrigeration
when swiching ac equipment to 410a from r22,do you have to repace line sets.can you flush them out? how do you know if they have leaks? what if ther might be soft sodder joints somewhere?just in general what are companys doing out there with this new situation. i am a tech and have flushed a few but am wondering about the issues. thanks

Comments

  • yesindeed
    yesindeed Member Posts: 13
    Student

    The operating temperatures and pressures of R-410A is much higher than R-22 therefore line sets will require replacing. The liquid line set maybe reused if it is sized correctly and cleaned properly. When in doubt the system manufacturer should be contacted.
  • yesindeed
    yesindeed Member Posts: 13
    Student

    The operating temperatures and pressures of R-410A is much higher than R-22 therefore line sets will require replacing. The liquid line set maybe reused if it is sized correctly and cleaned properly. When in doubt the system manufacturer should be contacted.
  • furnacefigher15
    furnacefigher15 Member Posts: 514
    Not true

    While it is best to replace the line sets, in some cases it is either not possible or no economically feasible (especially in condo's)



    If the old line set is exposed then replace it. If not, try re-rerouting a new line set. If there is no other feasible option, a line set can be re used, with a little effort.



    Be aware, in some cases it will be more expensive to re-use a line, then run a new one due to the time spent in prepping the line set for re-use.



    To test for leaks, braze shut each side of the lineset (sometimes brazing the liquid line into the suction will work as well on one end only) on one side of the line(s) add a pressure port, and fill the line(s) with nitrogen to 100 psi or so. Wait 2 hours and if the pressure is the same, the lines are leak free.



    The lines can be flushed using Rx11 flush or other approved compound following the directions within.



    The fact of the pressure difference between r410a and r22 is irrelevant. The copper used in either system is the same. (type ACR rigid, or soft rolled copper tubing)



    The only issue may be line sizing of the suction line. Also look for existing suction traps and remove them.



    The vacuum may be difficult to pull, so try using a tripple evac method. Evac down to 1000 micros, then break with nitrogen, wait 5 minutes, and purge nitrogen out then pull a new vacuum. Repeat three times, and the third vacuum should be able to pull to 500 microns. Be sure to purge nitrogen (at a trickle) while brazing in connections. Also do not make connections in the rain when possible.



    Note: line set re-use is nothing new, and neither is poe oil. In the refrigeration world, we've been dealing with it since r12 was phased out.
  • Paul_69
    Paul_69 Member Posts: 251
    yapindeed

    thx furnace fighter for knowledgeble responce. yapindeed saying i am a student and the giving out bad info is a joke. i am a 30 yr. tech just discussing this new situation for ac techs.i have concerns getting the 410a mixing with the r22 and was just seeing what other techs are doing. this might be old for refigeration guys but not a ac guy like myself. i like to run new lines also when all possible. just was throwing it out there for other opinions...
  • meplumber
    meplumber Member Posts: 678
    The lineset has nothing to do with pressure Yesindeed.

    It is all ACR tubing. The concern is whether there are soft soldered joints in the piping. Aside from that, follow furnacefighters advice. He is spot on.
  • Eugene_Silberstein
    Eugene_Silberstein Member Posts: 349
    Cannot Be Stressed Enough

    Now that we are on the topic, as mentioned, it is very important to push nitrogen through the lines when brazing. This is especially important when dealing with R-410A systems. The ester-based lubricant has a relatively strong scrubbing effect on the interior surfaces of the piping materials. This scrubbing effect can free any oxidation that might have formed on the interior piping surfaces during brazing.



    By passing nitrogen through the lines during the brazing process, we are removing the oxygen from the pipes and, therefore, the ability to oxidize.



    Uniweld has a really neat flow indicator that let's you know that nitrogen flow is present, especially at very low pressures.



    http://www.uniweld.com/index.php/productlisting/details/798/361/nitrogen-and-co2-kits/nitrogen-flow-indicator



    Have fun!
    Eugene
  • Empire_2
    Empire_2 Member Posts: 2,343
    Paul

    I did not catch any condescending remarks from first responder.  Did I miss something?  I know all of us respectfully try to answer any question.  I think he stated to consult manftr.  to see what their procedures are.   I know I do if I have a Q:?



    Mike T.
  • furnacefigher15
    furnacefigher15 Member Posts: 514
    No problem

    I think that's why were all here. To try and learn something, or offer advice, or both.



    As far as solder vs braze, I've heard arguments for both. I personally use braze.



    The real potential issue with solder joints is not strength, but the acids in the flux. The poe oil will pick up the flux and bring it back to the compressor. The only way to deal with such contamination is with filters.



    Food for thought. Most braze joints are actually weaker then solder joints. The reason is that in order to braze, the copper has to get much hotter. This excess heat will fatigue the copper by removing the temper of the copper.
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