Page 2 of 2 FirstFirst 12
Results 14 to 21 of 21

Thread: Rtaa retrofit

  1. #14
    Join Date
    Apr 2012
    Location
    Louisiana
    Posts
    897
    Post Likes
    FYI 407c evaporator glide is generally said to be 8 degrees F.

    The bubble and dew are 11 degrees apart at a normal evaporator pressure. Flash loss will never allow the bubble temperature to be reached in an evaporator.

    Average evaporator temperature will be four degrees less than the dew.

    Im not sure how many orings are in the system but as mentioned in a post above, they will need to be changed.

    Also, I normally start with 90 percent r-22 nameplate charge and adjust as needed.

  2. #15
    Join Date
    May 2015
    Posts
    1
    Post Likes
    Since R22 is so expensive now, what does everyone think now about converting the RTAA?

  3. #16
    Join Date
    Nov 2007
    Location
    Mississippi
    Posts
    1,500
    Post Likes
    This is an old thread, but is now more relevant than ever. At this point, I still haven't tried a retrofit, but I can see it in the near future. I still haven't heard of anyone else trying it either. Maybe someone will chime in with some experience.


    Have wrench-Will travel

  4. #17
    Join Date
    Apr 2013
    Location
    Portugal
    Posts
    60
    Post Likes
    RTAA EXV is controlled by the difference of the two temperature sensors mounted on EXV expansion side and suction. There´s no pressure reading, so it will be no problem controlling it with R407C. But one thing I tell you, you´ll have to get the next size of EXV, or try to open the orifice...

  5. #18
    Join Date
    Aug 2006
    Location
    Mixing oil and fire with a big spoon.
    Posts
    5,379
    Post Likes
    Quote Originally Posted by DigtalCracHead View Post
    Since R22 is so expensive now, what does everyone think now about converting the RTAA?
    i think the same as i did before. not a good idea. fix the leaks and leave it alone. in every case i found (theoretically), R407c costs you more in energy costs. R22 is a fixed, one time cost. the energy used is EVERY time the compressor runs. add in a small leak and with R407c you are most likely recovering and replacing all of the refrigerant (fractionation). with R22...top it off. that is cheaper, too.
    Someday, I hope to be just as brave as Harry Stamper.

  6. Likes stanbyyourword liked this post
  7. #19
    Join Date
    Oct 2010
    Posts
    234
    Post Likes

  8. #20
    Join Date
    Dec 2013
    Location
    Russia
    Posts
    105
    Post Likes
    1. Remove all the automation of Trane.
    2. Install the new controller, allowing screw compressor control in the continuously variable mode. It will be easier and cheaper than to invent a bicycle with square wheels.
    3. Set more powerful fans (condensers power decreases by 12% at the transition 407)
    4. Oil, sensors, all for a replacement.
    5. Wash all the old oil from the evaporator.
    6. Forget it and buy a beer.

  9. #21
    Join Date
    Jul 2007
    Location
    The Hot South
    Posts
    1,630
    Post Likes
    Trane doesn't have an official retrofit solution in the States and I've never tried it but there is a set point in the bottom of the configuration menu to select the refrigerant in the machine. The choices are R-22, R-134A, & R404A and the pressure- temperature relationship on the display corresponds with the refrigerant setting. This setting is in the UCP2 style controller factory installed on the 70-120 ton chiller. The larger RTAA's can be retrofitted with this controller also. I can't remember on the older style controller if there is a refrigerant setpoint.

Page 2 of 2 FirstFirst 12

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Related Forums

Plumbing Talks | Contractor MagazineThe place where Electrical professionals meet.
Comfortech 365