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  1. #1
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    Sep 2004
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    This may have been answered before but the R410a refrigerant is a Zeotropic Blend (A Zeotropic refrigerant when used in a refrigeration system has volumetric composition and saturation temps changes) of 50% HFC R32 with a molecular weight of 52 and 50% HFC R125 with a molecular weight of 120. now if you have a leak in a system fully charged with R410a and loose say onehalf the refrigerant charge can you just shoot some more of the blend in or do you have to recover what is left and recharge with virgin R410a blend? With the molecular weights being so far apart it would almost seem that if a leak developed one of these refrigerants would leak out faster than the other, leaving a incorrect mixture in the system? If you added some back in you would have a messed up system with some crazy pressures/temp glides?. If that is indeed the case the maintenance on the r410a units will be costly there will be no way to recover and reuse any refrigerant from a system that has leaked?
    When you give a lesson in meanness to a critter or a person, don't be surprised if they learn their lesson.

  2. #2
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  3. #3
    Join Date
    Apr 2004
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    Its a near azeotropic blend. No you can add refrigerant. (you still need to reapir the leak).

  4. #4
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    Oct 2004
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    Norm's article does say it all !

    Doc, yes you can just add, as long as the leak is fixed, but the concern is the moisture issue with POE

  5. #5
    Join Date
    Apr 2004
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    I am aware of moisture worry. Assuming you only loose half the charge, you will still have positive pressures maning you will not likely pull moisture in the system. This whole moisture thing and the seperation of refrigerant is overplayed by the ones looking for a reason to be scared of R-410A and POE oils. (not you, but in general). Follow good refrigeration practices and change the drier everytime you open a system, get over pressures and start reading saturation temps and you will have very few issues.

    Personally if I have to recover up to half the charge of R-22, to repair a leak, I dont even consider putting it back into the system. If I gotta garuntee my work, I am not about to reinstall old refrigerant from the depths of who knows what kind of crap has been in the tank back into the system.


    OHHHH LOOOKIE!!!!!!!!!! 3000 posts!!!!!

  6. #6
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    Oct 2004
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    #1, Proud that your reply to me was #3000

    #2 I am in total agreement with what you say, and yes, I think it is overplayed by those afraid of 410 as well.
    It was one of those general random thoughts that came out of my brain !!

  7. #7
    Join Date
    Sep 2004
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    172
    dang boys I read that norm thing twice and cannot find the info about the blend leaking out evenly, someone please cut and paste where it says the blend will leak out at the exact 50/50 ratio. I was thinking that it would be darn near impossible for that to happen! I guess somewhere someone has done some testing on that?
    When you give a lesson in meanness to a critter or a person, don't be surprised if they learn their lesson.

  8. #8
    Join Date
    Sep 2002
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    South Dakota
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    Originally posted by dnt
    dang boys I read that norm thing twice and cannot find the info about the blend leaking out evenly, someone please cut and paste where it says the blend will leak out at the exact 50/50 ratio. I was thinking that it would be darn near impossible for that to happen! I guess somewhere someone has done some testing on that?

    It is the part where I state that the temperature glide is only .3 degrees F. The small temp glide means that the leakage rate for the mixed refrigerants is that minimal. Nearly identical!


  9. #9
    Join Date
    Sep 2004
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    172
    Norm help me out here a bit, isn't the reason the temp glide is so small is because of the 50/50 mixture used to make up the blend, if that was turned into a say 75/25 by uneven leakage would that not change the temp glide drastically? Not trying to start a argument just trying to make sense out of using a blend, I was taught that if they leak you have to recover and install all new to keep the correct ratio. Please post if you have a link that will lead to some real world testing results that have been performed as I am extremely interested tks darryl
    When you give a lesson in meanness to a critter or a person, don't be surprised if they learn their lesson.

  10. #10
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    South Dakota
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    Originally posted by dnt
    Norm help me out here a bit, isn't the reason the temp glide is so small is because of the 50/50 mixture used to make up the blend, if that was turned into a say 75/25 by uneven leakage would that not change the temp glide drastically? Not trying to start a argument just trying to make sense out of using a blend, I was taught that if they leak you have to recover and install all new to keep the correct ratio. Please post if you have a link that will lead to some real world testing results that have been performed as I am extremely interested tks darryl
    The close temperature glide and nearly identical leakage rates is mostly due to the fact that the two refrigerants share nearly identical saturation temperature-pressure relationships.


  11. #11
    Join Date
    May 2002
    Location
    Houston Texas
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    6,321
    I had unit today Amana RSG installed in February I apparently made a bad weld. It leaked out about half the charge apparently in the last few days. It was in the suction line at the evap.
    Found the leak pump refrigerant into condenser coil recovered last little bit (never pump a scroll into a vacuum) and repaired leak. While pulling a vacuum on the coil and line set I did a static test of the refrigerant in the condenser. Disconnect the compressor and run the fan until temp across condenser coil is zero checked against PT chart almost spot on. After evacuation released charged and toped of. Everything should have been fine but I had 71 degree SC. I couldn't figure it out talked with Amana tech rep we went over every thing airflow setting on furnace the works.
    After going over every thing in the attic went outside and noticed that my gauges were set to R-401 not R-102. I use Digi-Cool gauges and they work on 22 refrigerants. It is nice to have neat tools but in this case I wasted about 4 hours and allot of worry. I guess I will double-check what refrigerant they are set on.
    The good thing is when I set them on the right Refrigerant all it took was a slight adjustment and every thing was just fine. There is no problem with the refrigerant even after losing part of its charge as long proper procedures are followed.

  12. #12
    Join Date
    Sep 2004
    Posts
    172
    tks big c that really is some real world testing thanks. It seems sometimes that all the pains we go to to get something just exactly right really do not matter that much I am with you man don't worry be happy and never try to invent a problem where there is not one. Quote from cowboy guide to life "If you find yourself in a hole, the first thing to do is to stop digging" I am going to go study on some pressure/enthalpy diagrams to get my mind off of R410a I just cannot get my brain to understand these silly things. Maybe tommorrow. hmmm
    When you give a lesson in meanness to a critter or a person, don't be surprised if they learn their lesson.

  13. #13
    Join Date
    Mar 2003
    Location
    North St Paul MN
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    858
    Here is a somewhat related question. The guy I worked for a few years ago insisted that if we had to charge or adjust the charge on a 410A system, we had to charge by vapor. (Takes a long time when you have to keep running for warm water to fill the 5 gallon bucket.) He was fearful that we would slug the compressor-MORON! Anyway, how would this affect the mixture not only in the unit, but in the remainer of the jug as it gets close to being empty?

    [Edited by markco on 05-17-2005 at 02:02 AM]
    I'd rather have a bottle in front of me, than a frontal lobotomy.

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