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Thread: cooling problem

  1. #1
    Join Date
    Apr 2003
    Posts
    27
    I was working on a split system two and one half ton. Carrier 38tra030 approx 12 years old. The complaint was at night it gets cool but during the day the temperature goes up. Here are the pressures I found, hp195 bp 75 sution temp 46 deg, outdoor temp. 90 deg. The system has an accurator on it. My superheat is 2 deg. I thought perhaps the system was overcharged. Recovered approx 2 pounds. No change. The discharge air was 70 deg. The room temp was 77deg. Checked the indoor coil and duct work in the attic. The coil was clean and the duct work was all attached and insulated. Need some suggestions.Could it possibly be bad discharge valves on the compressor? Thanking you in advance.

  2. #2
    Join Date
    Dec 2004
    Posts
    201
    What type of metering device do you have in the airhandler?

  3. #3
    Join Date
    Apr 2003
    Posts
    27
    a # 59 piston

  4. #4
    Join Date
    Aug 2002
    Posts
    490
    the suction line is cold and the pd is low to much refrigerant is flowing, also not enough heat is being absorbed.
    could large orifice or open expan. valve

  5. #5
    Join Date
    Dec 2004
    Posts
    201
    I would try and pump the unit down, this can help to determine if valves are ok.

  6. #6
    Join Date
    Apr 2003
    Posts
    27
    I will try to pump down when I go back.

  7. #7
    I think that system takes a 67 piston. Could be wrong.

  8. #8
    This system does take a #67 piston. I would recommend recovering the refrigerant rather than pumping the system down as it may have non-condesibles in it. Also, make sure that the outdoor coil is clean before weighing in the charge.

  9. #9
    we need subcooling to determine your problem.
    but low superheat high suction suggests either overcharge or
    oversized piston.now if the subcooling is high then your overcharged and if its low then orfice is to large. 67 orfice is usually a 2.5 ton

  10. #10
    Join Date
    Dec 2004
    Location
    Derby City
    Posts
    3,973
    Good conversation between techs. but this should be taking place on the pro page. Start talking about 'recovering refrigerant' and piston sizes, etc. on this public access site, and you know what will happen.

    Not critical of the exchange, just the location.
    Everyone has a purpose in life..........even if it's to be a bad example.

    Seek first to understand, before seeking to be understood.

  11. #11
    Join Date
    Aug 2003
    Location
    Central Kentucky
    Posts
    6,248
    Did you verify how much air the fan was moving across the evaporator?
    Have you set up a Google alert for Carbon Monoxide yet?
    Click here to find out how.

  12. #12
    Join Date
    Apr 2003
    Posts
    27
    The subcooling was 5deg.

  13. #13
    38tra30 is a 2 and a half ton unit.

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