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  1. #1
    Join Date
    Jul 2007
    Posts
    74

    Carrier Puron 410A system problem.

    If you have a 13 seer, 3 1/2 ton Carrier Puron system. Has a factory installed TXV installed on the evaporator. System pressure run 125 low side and 365 on the high side. Liquid line temperature reads 99 degrees which corresponds to the 11 degree subcooling required. After system pressures equalize and system is restarted the low side pressure will slower decrease, within 15 to 20 minutes the pressure will be down to 80 or 90 and will start frosting up all the way to the condenser. Head pressure stays the same and after 15 minutes the liquid line temperature starts dropping. TXV bulb is mounted correctly, there is adequate airflow across the coil. When the bulb is disconnected from the suction line the the same result. Just wondering what anyones answer to this problem would be.

  2. #2
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,150
    Once you get into the frosty state, what are your superheat and subcooling readings? What is the return air wet bulb and dry bulb?
    Perhaps you should have read the instructions before calling.

  3. #3
    Join Date
    Jul 2007
    Posts
    74
    Lower subcooling. Higher superheat. 80 degree dry bulb and 68 degree wet bulb.

  4. #4
    Join Date
    Jul 2007
    Posts
    74
    l
    Last edited by NeTech; 07-18-2007 at 09:56 PM.

  5. #5
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,150
    Is this an N coil? How long has it been installed?
    Perhaps you should have read the instructions before calling.

  6. #6
    Join Date
    Dec 2002
    Location
    omaha
    Posts
    343

    Smile

    replace txv and try again

  7. #7
    Join Date
    Jul 2007
    Posts
    74
    It is an N coil. Has been installed 2 weeks. Homeowner says it ran too much and would never pull the temperature in the house below 80 degrees. Best temperature drop I got was 12 degrees.

  8. #8
    Join Date
    Jul 2007
    Posts
    74
    Replacing the TXV was what I was going to do, have one on order. For some reason there was not one on stock.

  9. #9
    Join Date
    Jul 2007
    Posts
    74
    Didn't know if there was something I was missing.

  10. #10
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,150
    Does the coil fit the furnace or overhang? If it overhangs, which direction?

    I've seen N coils installed incorrectly (http://www.docs.hvacpartners.com/idc...m-cnpvp-01.pdf) as shown on page 4 in Alternative A and D. D is the worst. Most guys won't make a transition. So, C is the answer.

    I'm not saying the TEV isn't bad, but I'd look darn close at that coil first because it operates okay for a bit. Usually a bad TEV will pump down immediately. Your system is taking some time like some airflow is missing across part of the coil (Alternative D causes this).
    Perhaps you should have read the instructions before calling.

  11. #11
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,150
    Alternative D is the one with the WRONG label.
    Perhaps you should have read the instructions before calling.

  12. #12
    Join Date
    Jul 2007
    Posts
    74
    The installer put the coil in the existing plenum since it was easier and the furnace was not replaced. Coil sits in the center of the furnace. When I saw the evaporator half covered in ice the first fix was fill in the 3 in gaps on each side of the coil, since air will take the easiest route around the coil. Its a 16" wide coil sitting in a 20" or bigger plenum.

  13. #13
    Join Date
    Jun 2001
    Location
    Louisville, KY
    Posts
    12,150
    Good chance the existing coil supports are covering the right side of the N. I have pics somewhere showing just that.

    There are a couple of places at the top of the N to shoot screws from the side instead of using support rails on that side.

    Good luck. Let us know what you find.
    Perhaps you should have read the instructions before calling.

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