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  1. #1
    We installed a new furnace/indoor coil recently. We oversized the coil by 1/2 ton. We put in the piston that that matches the condenser (we think), and our pressures and TD is not working out.

    We can only get a 10-12deg TD across the coil, and had to overcharge to get that.

    I'm sure my boss will have it worked out by the time I get any answers to this, but what am I looking at?

    Thanks

  2. #2
    Join Date
    Apr 2002
    Posts
    1,604
    I can't imagine the factory packing the wrong size piston can you??

    Ive seen pistons put in backwards in ICP coils that caused press probs.
    "The Bitterness of poor quality remains long after the sweetness of low price is forgotten"

  3. #3
    I think that's where the problem is. The condenser is a York, and the coil a Bryant.

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,766
    I'd check the piston first. What size do you think you have in it.
    Then I'd check the air flow.

    What size condenser, and what size blower, set for how much CFM.
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  5. #5
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,509
    when you say overcharged i am not sure what you mean. you installed the piston that came with the condenser or the one the coil book called for with that size condenser. next did you do superheat or subcool or just the old idiot rule 30 degrees above the outside temp. not trying to be rude but let us know how you charged the unit and presures you had with temps to. out side inside and suction temp liquid temp. td across the coil and supply register and return intake. did you use staybrite with flux or braze the lines
    posible the screen at to orfice is clodged with flux or other particals. mixmatching brands is sometimes tuff the orfice might be right for one system and not the right one for another

  6. #6
    Join Date
    Apr 2004
    Posts
    7,680
    Let me get this straight. You installed, on purpose, a mismatch not only in size but brands and wonder why you are having problems? Then you charge a system by temperature drop and further, to resolve the issue you overcharge the unit to compensate. I sure hope York and Bryant dont get any blame in any of this one.


  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,766
    Doc.
    You know its those darn junk Bryant coils.
    Or those garbage Bristol compressors that York uses.

    LOL...
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  8. #8
    install a txv and be done with it.

  9. #9
    Join Date
    Jan 2005
    Location
    Perth - Western Australia
    Posts
    775
    yeah, dont be cheap install a txv

  10. #10
    Sorry guys, I know it isn't the ideal situation. The customer did not want to upgrade the condenser.

    And as for charging method, I was only the helper on site.

    I do know that return temp was 74 and supply was 60.

    I was told that the startup guy is doing some research to find out which piston to go with. He did use the recommended piston for the condenser size.

    Also, all joints were brazed. (Sil-Phos)

    I'm just trying to learn, thanks for the input.

  11. #11

    Hmm

    Does anybody out there use flux when pertaining to an air conditioner? Hope not!

  12. #12
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,509
    desert tech
    i hear you but in jersey staybrite solder is very popular and should be uesed with stayclean flux. i although still braze line sets and coils i have used it in tight places and found it to be safer than brazing. you should look into it great when the line is only a few inches from the wall. staybrite flows at about 400 degrees i believe and holds up to 10,000 pounds presure. the spects are on the box.

  13. #13
    Join Date
    Dec 2002
    Location
    in a house, Appomattox, Va.
    Posts
    3,191
    Airflow, Airflow, CORRECT AIRFLOW? then charge
    Col 3:23


    questions asked, answers received, ignorance abated

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