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  1. #1

    single to a dual circuit

    I am changing out a 7.5 ton R-22 single circuit AHU, to a 7.5 ton 410A dual circuit. I know i have to change expansion valve back to R-22. But what else?

  2. #2
    Join Date
    May 2003
    Location
    Charleston SC
    Posts
    123
    I assume you are changing the outdoor unit to a 2 compressor setup where you will be running at approx. 50% capacity most of the time. I would get the information off the valve and check it out with the manufacturers specs. to see if it will control under reduced volume conditions. If its an OEM valve with no info, you may want to research the Sporlan web site. Its a pain to change a TXV but not as much a pain as callbacks.
    Regards
    Coolairman

  3. #3
    No! Some people bought a ahu to replace their leaking coil one. Thier old unit is a r-22 single circuit. They were told that no more R-22 AHU 7.5 ton can be found so they bought this dual circuit 410A AHU. I know i can change it over to r-22 but how about the dual circuit?

  4. #4
    Join Date
    Feb 2003
    Location
    Wichita Ks
    Posts
    1,502
    2 expansion valves, tee the liquid line together and tee the suction together. mount the sensing bulb to its own suction line for that circuit.

  5. #5
    Ok! Then use two 3.5 ton expansion valves? And also use long radius ells, but how about the tees they will be straight?

  6. #6
    Join Date
    Aug 2011
    Location
    Salem Oregon
    Posts
    26
    The dozen installs I've seen with tees used regular tees. Though if you are concerned about equal flow, you might put the liquid line into the branch and out the sides to the txvs.

  7. #7
    Join Date
    Aug 2012
    Location
    Palmyra, Missouri, United States
    Posts
    224
    Just did this last friday.. use two exspansion valves then tee liquid line together. also tee suction lines together and strap bulbs to the suction line before the tee on each circuit separately.

  8. #8
    Ok Thanks will try wed. How about the txv sizes?

  9. #9
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    sporlan has decent Tech help...ive been at united trying to select an item and the counter has called them to assist us in selection.

    Or download their catalogues and see if you can figure it out,their cats have selection guides.

    There is more to it than just tonnage...

    if it was me I would call sporlan and explain what I was doing. I bet they will point you in the right direction.... And save a callback or eliminate system issues

    Just my opinion...
    mikeacman

  10. #10
    Join Date
    Aug 2012
    Location
    Palmyra, Missouri, United States
    Posts
    224
    Get4 ton valves

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