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  1. #1
    Join Date
    Aug 2001
    Location
    Miami, FL
    Posts
    111

    Confused

    Hi guys..I hope someone can give me an answer:

    Replaced a 4 ton (TCD048 Rooftop) Trane Compressor, which was as well replaced by a Tecumseh like 2 yrs ago.
    I installed a NEW (Sealed) Copeland Hermetic 47,000 Btu/h 3PH 230V.

    The old compressor's coil was grounded. Compressor burned.

    I pulled all the R22 out, and cleaned the system with N2. Installed new compressor. After all solderings, I pulled high Vac for 30 min. Charged and tested, pressures were good. 65LB/240LB 88F Outdoor.

    Problem:
    Inside temp only 10F bellow Outdoor temp. I get 78F from any supply register.
    Any clue?



  2. #2
    Join Date
    Aug 2001
    Location
    Miami, FL
    Posts
    111

    by the way...

    by the way, I charged by weight and charged with 12LB R22 as says in the plate.

  3. #3
    Join Date
    Dec 2002
    Location
    SouthEast NC ICW & Piedmont Foothills
    Posts
    7,635
    Did you replace the driers?
    Are you running 100 o/o outside air?
    It`s better to be silent and thought the fool; than speak and remove all doubt.

  4. #4
    Join Date
    Aug 2001
    Location
    Miami, FL
    Posts
    111

    Sure!

    Of course, I did replace the filter...I found some dust inside the piping so I used N2. Then I installed the filter and did the solderings connecting the new compressor.

    Another question.....Shoud I have add some suniso oil?


  5. #5
    Join Date
    Apr 2004
    Posts
    161
    Just curious, but what is the return air temp before evap?

    That 88 degree outdoor, did you actually measure that near condenser on roof?

    That suction pressure looks a bit low if your return is warmer than 75 degrees or so.

    I wouldnt think the economizer is open with that low suction press.

    Can you measure temperature drop across evaporator coil,return and supply temperatures and measure suction line temperature near compressor while taking pressure readings and outdoor ambient near condensor please and post all here?

    That will help us to try and get you some answers.

  6. #6
    Join Date
    Aug 2001
    Location
    Miami, FL
    Posts
    111

    Post Ok..

    88F near condensor.
    Yes, suction pressure seem to be too low.
    I think it shoud be like 75, correct?

    I will go and take temperature/pressures readings again tomorrow if needed.





  7. #7
    Join Date
    Aug 2001
    Location
    Miami, FL
    Posts
    111

    No economizer

    Unit does not have economizer.


  8. #8
    Join Date
    Apr 2004
    Posts
    161
    Actually I dont think anyone can give you an accurate answer on what suction pressure should be untill the return/supply temperatures are known along with other goodies I mentioned.

    If I had around 80 deg return I would expect near 75/80 psig, but I suspect your return temperature was higher than that considering you had a 78 degree supply after you started up and seemed some cooling was getting done with those pressures you mentioned.


    Trust me, you will get some good answers here when you get the info.






  9. #9
    Join Date
    Jun 2001
    Location
    Northwest Indiana
    Posts
    1,302
    Was trane out of compressors?
    Why the re-engineering on a tcd048?
    Copeland? Techumseh?
    I did not know they made replacements for trane, then again, I don't get out much!!
    Bernie
    If you cant fix it right, try again.

  10. #10
    Join Date
    Aug 2001
    Location
    Miami, FL
    Posts
    111

    ok..

    yes, they told me the trane compressor would take 1 week ans cost $750...very expensive, the costumer will not pay that much for all the work.
    Copeland came with $350 for same btu/h and performance.


  11. #11
    Join Date
    Jun 2004
    Posts
    160
    Originally posted by Gabrielnqn
    Hi guys..I hope someone can give me an answer:

    Replaced a 4 ton (TCD048 Rooftop) Trane Compressor, which was as well replaced by a Tecumseh like 2 yrs ago.
    I installed a NEW (Sealed) Copeland Hermetic 47,000 Btu/h 3PH 230V.

    The old compressor's coil was grounded. Compressor burned.

    I pulled all the R22 out, and cleaned the system with N2. Installed new compressor. After all solderings, I pulled high Vac for 30 min. Charged and tested, pressures were good. 65LB/240LB 88F Outdoor.

    Problem:
    Inside temp only 10F bellow Outdoor temp. I get 78F from any supply register.
    Any clue?


    Did you clean the condensor coil?

  12. #12
    Join Date
    Aug 2001
    Location
    Miami, FL
    Posts
    111

    Question Clean?

    What did you mean? If I cleaned the condensor using a coli cleaning agent? No I did not. And it doesn't seam bad.

  13. #13
    Join Date
    Jul 2004
    Location
    La Porte,IN
    Posts
    8

    Trane RTU/Low Supply Air Temp

    What is Delta-T @ Evap Coil? Cap Tube or TXV? Subcool & Superheat need to be checked. Previous replacement may not have been charged properly. Trane has great tech support but make sure you have all info above along with pressures b4 talking to them. Also M# & S#.

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