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  1. #1
    Join Date
    Sep 2003
    Location
    Ocean County, N.J.
    Posts
    484
    Don't have model and serial #s, but it's a 1 yr. old 3 ton 10 seer Goodman condensig unit. Fan runs, compressor won't start. I have not personnally been to this call, but the tech who was there told me everything he saw was o.k. and wants to install a hard start kit. I want to check the windings in the compressor first ( going on the information he gave me ). If I were to ohm the compressor out, approx. what would be considered acceptable values to look for? He claims all connections are in good shape, but he can't hear compressor even attempt to start.

  2. #2
    Join Date
    Feb 2005
    Location
    Dothan, Al
    Posts
    3,453

    Jack D

    For single phase:.8 to 1.8 ohms(approx) - common to run
    2.5 to 3.8 ohms(approx) - common to start
    run to start = equal to sum of the other two

    For three phase: all windings read approx. .8 to 1.4 ohms

    Check compressor amp draw, see if it is pulling locked-rotor when energized, if so then superboost it, if not, other problem.

    Hope this helps
    Richard

  3. #3
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Did he check to see if it's grounded? Also check terminals right on compressor(hard to see sometimes). If it's not even attempting to start,I don't see where a hard start will help you.
    If everything was always done "by the book"....the book would never change.

  4. #4
    Join Date
    Dec 2003
    Posts
    165
    They didnt amp it? You dont just start adding things to a unit until you know what is going on with it. Check the existing capacitor with a cap. meter and amp the compressor on start up. The ohm values should be the lowest number between c and r. The next highest number should be between c and s. The highest number should be from s to r and that should be c to r and c to s added together. If you get OL between c and r and c and s you could have an open Thermal overload. Make sure the comp. is cooled down to the point where the overload can close back before you condemn it.

  5. #5
    Join Date
    Dec 2003
    Posts
    165
    Also....check your cunductors between the contactor and the comp.

  6. #6
    Join Date
    Sep 2003
    Location
    Ocean County, N.J.
    Posts
    484
    I want to thank all of you for your time, you've all been very helpful. Schmuch, I agree with you about just blindly installing parts. The tech says the 3 lugs on compressor are in good shape. Remember, I wasn't there, but I would like to resolve why the compressor isn't even making an attempt to start before I do anything. I expect to go there tomorrow.

  7. #7
    Join Date
    May 2004
    Location
    Canada
    Posts
    317

    Talking


    Holy bad capacitor Batman.....

  8. #8
    Originally posted by smokin68
    Did he check to see if it's grounded?
    Do you think the condenser fan would still be running?

  9. #9
    Originally posted by tlchvac

    Holy bad capacitor Batman.....
    I say BINGO!

    Make sure you have a 5/35 MFD 440 V cap!

  10. #10
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Originally posted by jultzya
    Originally posted by smokin68
    Did he check to see if it's grounded?
    Do you think the condenser fan would still be running?
    Sounds like the internal overload is stuck open,but I didn't see condenser fan in his post, I saw fan runs,which could be the A/H, but I'll give you credit for your sharp troubleshooting skills.The way I've seen some wired up(fuses missing) it is possible though,just not likely. I was just trying to help before wasting $$$ on a hard start kit. The amp draw will tell the tale.Since I have all new units where I work I'm getting rusty,that's why I come top this site,to try to retain some of my HVAC info that's been torched into me.
    If everything was always done "by the book"....the book would never change.

  11. #11
    Join Date
    Sep 2003
    Location
    Ocean County, N.J.
    Posts
    484

    Ohming Goodman compressor

    Met original serv. tech. at call. Called for cooling, unit ran fine. Checked pressures and temps: O.K. Shut unit down, let pressures equalize, then called for cooling again. Started right up, ran fine. Took some measurements: 120 volts to run and common on compressor, start winding was 374/380 volts on start up, and after it ran for a few minutes, 314 volts. Amps. came up at 11.3 & 10.85 for run and common, with 5.3 for the start winding. What is taking place? Are these acceptable values? Unit is 1 yr. old. It has a 35/5 370 cap. I recommended to the tech. (it's his call) for him to install a 35/5 440 before he were to put the hard start kit on and see what happens. Was I wrong?

  12. #12
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Why the hard start? It started right? Check the subcool/superheat and the OFM,something caused thatcompressor to heatup and trip the IO.
    If everything was always done "by the book"....the book would never change.

  13. #13
    Join Date
    Sep 2003
    Location
    Ocean County, N.J.
    Posts
    484
    The hard start kit was not my idea, in fact I'm trying to avoid using one by finding the problem vs. just putting on a band aid. S/H and S/C are fine. So ,again, can someone tell me if the voltage and amp. values are acceptible? Also does the fact that I'm seeing up to 380 volts on a 35/5 370 cap have something to do with why it didn't start up in the first place, and would it help if the 35/5 370 cap was replaced with a 35/5 440 cap? Did I give the original tech. an accurate piece of advise?

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