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Thread: carrier rtu

  1. #1
    Join Date
    Apr 2004
    Location
    Fort Worth, Texas, United States
    Posts
    86
    changed out o6d compressor on a carrier mod.48tjdo16.weighed in charge of 19.3#s but was running 70 amps with fla of 61.recovered some refrigerant this is my info.l1-l2-199v,l1-l3 199, l2-l3 200v,67,62,63 amps.75#s suction,295 head pressure.20deg. s.h.,3deg. subcooling.86 return air,67 supply air backed exp valve all the way out trying to lower superheat from 30 plus degrees.ambient temp 101.i sshould have taken oil press. but didnt i have heard this particular model has had its share of factory problems such as airflow over both coils its also next to exhaust off of a tortilla oven and it serves the kitchen area.anybody have any thoughts appreciated .

  2. #2
    Join Date
    Mar 2004
    Location
    Windsor, ON Canada
    Posts
    168
    What is your temp rise across the condenser?

  3. #3
    Join Date
    Apr 2004
    Location
    Fort Worth, Texas, United States
    Posts
    86
    i did not check temp rise across condensor

  4. #4
    Join Date
    Mar 2004
    Location
    Windsor, ON Canada
    Posts
    168
    Originally posted by hvacplumb
    i did not check temp rise across condensor
    Well, 295 with 100F amb isn't too bad I guess, what is the problem, is it not cooling or is it still over-amping?

  5. #5
    Join Date
    Apr 2004
    Location
    Fort Worth, Texas, United States
    Posts
    86
    yes 67,62,63 on 61fla

  6. #6
    Join Date
    Apr 2004
    Location
    Fort Worth, Texas, United States
    Posts
    86
    yes just worried about losing another compressor.

  7. #7
    Join Date
    Mar 2004
    Location
    Windsor, ON Canada
    Posts
    168
    Originally posted by hvacplumb
    yes 67,62,63 on 61fla
    Right...I forgot!
    go to the chat room

  8. #8
    Join Date
    Jun 2004
    Location
    Richmond Virginia
    Posts
    1,078
    Everything looks pretty good but it certainly never hurts to clean the condenser. Also, your line voltage is definately low which is going to cause the amps to creep up. Remember, that unit is made to operate from 208 to 240 volts. The RLA you speak of may be the rating at 230 or 240 volt. As your load drops (both outdoor and indoor temps) the amp draw should decrease also. High superheat on a hot day with a high return air temp is not unusual. You could be a tad bit low on charge. How much do you trust your scale?

  9. #9
    295 is too high, clean that pos.
    Hey cockroach, don't bug me!

    www.AskTheDiceman.com

    www.TheColdConspiracy.com

    www.Pennwood-HVAC.Com

    Bring Em Home....

  10. #10

    ...

    did you change the compressor contacter as well?

  11. #11
    Join Date
    Apr 2004
    Location
    Fort Worth, Texas, United States
    Posts
    86
    yes replaced contactor as well

  12. #12
    Join Date
    Mar 2004
    Location
    midwest
    Posts
    954

    Arrow

    Sounds silly but is the load a constant 86F return air??? Had some industrial customers using rooftops for plant that were undersized caused high superheat and overheating of compressors. Unless load comes down it might be undersized. Should get 20TD give or take on evap coil check air flows.

  13. #13
    Your amps dont look bad. Do a search on this site of RLA, FLA under the section on FYI.

    Also see if there are any data charts on the performance curve for this particular compressor.

    That chart(s) will tell you very clearly whether or not your unit is operating properly at the various voltages, amperages, pressures and temperatures.


    Clean the pig! Bring inthe variable pressure, hi pressure washer with solutaion.

    You just replaced the compressor. There is a reason that old unit died.

    Your words saying it is next to a roof exhauster is evidence enough that this arrangement needs to be modified immediately!!!

    A/C's and roof exhausters do NOT co-mingle well.

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