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  1. #1
    Join Date
    Jun 2006
    Posts
    13

    Confused

    Attempting to save money changing out a 19 year old 5 ton trane condensing unit and air handler with heat strip, I bought some 3 year old Lennox 5 ton equipment. The Condensor is a non-heat pump unit, scroll compressor and used with R22. The Air handler is a Lennox (CBX32MV) variable speed that was charged with 410 (Puron). I had an HVAC contractor over today to look over and bid on the installation and he isn't sure if R22 will work correctly with the coil/expansion valves in the air handler. The lennox manual for the air handler states that the internally mounted check/expansion valves are suitable for use in R410A applications, that leads me to think that they should also be compatible with R22? Has anyone had experience with this type of equipment change out before and if so were ther any problems my tech should be made aware of. He's kind of leaving the decision up to me and I have no clue. Thanks for your help.

  2. #2
    Join Date
    Jun 2006
    Posts
    13
    After reading through many replies to other peoples questions it looks as if saving money isn't a good thing. I wish I had the funds to pay for a brand spanking new high efficient system, but I don't. I guess others don't know what it's like to raise a large family on a limited budget. sorry if my question irritated anyone

  3. #3
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    The expansion valve is generally the only difference between a coil for R-22 and one for R-410a.

    The R-410a expansion valve is most definatly not compatable with an R-22 system, so it would need to be changed.

    Good luck with it.
    If more government is the answer, then it's a really stupid question.

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,755
    As Mark said the TXV must be changed out.

    Also, was the old unit a heat pump.
    If it was, and you have them install a straight A/C with electric heat, your going to have electric bills 3 times as high as you did with the heat pump in winter.
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  5. #5
    Join Date
    Jun 2006
    Posts
    13
    The original unit is a straight cool condensor. We're in South Florida so heating expense usually isn't much of an issue and electric heat isn't uncommon. Is the expansion valve (TXV) something readily available? The tech was giving me the impression that the cooling produced may not be as good as if I was using a coil designed for R22, if the expansion valve was changed then theoretically there wouldn't be any difference between the two coils right? Thanks for your proffesional opinions

  6. #6
    Join Date
    Jun 2006
    Posts
    13
    Another issue is the remaining oil in the R410 coil right? Since the coil isn't hooked up yet is there a particular product or technique for flushing out the old oil before the new TXV was installed?

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,755
    Flush with RX11

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  8. #8
    When you remove the old TXV, put it in a ziploc bag along with a packet or two of moisture absorber and store it for future use.
    The expansion valve is generally the only difference between a coil for R-22 and one for R-410a.
    And a coil for R410a is made of thicker pipes to withstand the pressure.

  9. #9
    Join Date
    Jun 2006
    Posts
    13

    Wink

    Thanks for all the input! The tech was supposed to get back with me today with his thoughts on doing this job, but haven't heard from him yet. Anyway, when and if he gets back over here I will have some good suggestions for him. Would any 5 ton TXV designed for R22, using the same size tubing, be compatible? Or is there something specific he needs, like a Lennox part, etc.? Thanks again

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    67,755
    Originally posted by star882
    When you remove the old TXV, put it in a ziploc bag along with a packet or two of moisture absorber and store it for future use.
    The expansion valve is generally the only difference between a coil for R-22 and one for R-410a.
    And a coil for R410a is made of thicker pipes to withstand the pressure.
    Not always.
    Some manufacturers just tested their r22 coils at a higher pressure, and certified them for r410a.
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  11. #11
    Join Date
    Jun 2006
    Posts
    13
    I guess I'll let everyone know how it turns out, I'm going to see if I can come up with a 5 ton TXV and hope for the best. Thanks for everyones input.

  12. #12
    so 4 yrs later did it work can you flush out R-22 lines and re use with R-410a without issues? thx m.

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,755
    Yes, it works.
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