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  1. #1
    Join Date
    Jan 2002
    Posts
    255

    RTAC Compressor Terminal Sweating Issue

    Hi all, Got a call from a customer that they had to reset the front 500 amp breaker on a 2010 RTAC. I arrived at the job and the unit was running as normal. I got them to swap the unit over to a stand by to start checking it out. It was running at full capacity when I arrived. I started checking resistance and megging out things and noticed some odd readings on one of the compressors. I opened up the pecker head on the compressor and the terminals were just dripping wet. The shorting bars had an 1/8" of water standing on them and it was running down the studs. The meg reading was about 5 meg and when i dried it up it went to over 20?

    Has anyone else noticed this on their units? I don't know for sure if this was the cause but it seems very odd to me. I know Trane had issues on the old GP screws back in the day with straight top studs like this pooling water when you shut them down but thought they corrected it. Any ideas?
    Two wire hook up, three wire f**k up.

  2. #2
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,063
    Two choices ,
    1- liquid electrical tape and have fun once you dry the terminals off
    2- go to your local motor shop buy a couple of cans of the paint they use on motor windings and dry the terminals off and spray away .
    problem solved .
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  3. #3
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,720
    Quote Originally Posted by Healey Nut View Post
    Two choices ,
    1- liquid electrical tape and have fun once you dry the terminals off
    2- go to your local motor shop buy a couple of cans of the paint they use on motor windings and dry the terminals off and spray away .
    problem solved .
    Didn't have this issue on the RTAA's did you?
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  4. #4
    Join Date
    Mar 2004
    Location
    ottawa canada
    Posts
    2,063
    Quote Originally Posted by Dallas Duster View Post
    Didn't have this issue on the RTAA's did you?
    Yeppers
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
    You bend em" I"ll mend em" !!!!!!!
    I"m not a service tech.. I"m a thermodynamic transfer analyst & strategic system sustainability specialist
    Best Austin Healey In Show twice in 2013 .....All those hrs paid off .

  5. #5
    got an rtaa doing the same thing. number 2 is not wet at all. in the process of finding out why. shut them off for 24 hours new cc heat, valved off exv., oil line, discharge, waiting to see if it stops. will update

  6. #6
    Join Date
    Jun 2010
    Location
    U.A. (upper Alabama)
    Posts
    861
    Quote Originally Posted by bcooling1 View Post
    got an rtaa doing the same thing. number 2 is not wet at all. in the process of finding out why. shut them off for 24 hours new cc heat, valved off exv., oil line, discharge, waiting to see if it stops. will update
    There is a bulletin on the RTAA's. It says to clean, dry and use the liquid rubber as Healey Nut stated. I have had a CHHN compressor short out due to this. I think it is caused, not just by the moisture, but the dust that moisture collects. On this particular one the jumper bars (across the line start) had burn marks on them, but had already killed the motor windings.

  7. #7
    Join Date
    Apr 2012
    Location
    Paper Street Soap Company
    Posts
    2,304
    Quote Originally Posted by bcooling1 View Post
    got an rtaa doing the same thing. number 2 is not wet at all. in the process of finding out why. shut them off for 24 hours new cc heat, valved off exv., oil line, discharge, waiting to see if it stops. will update
    Had that happen on a RTAA 110, liquid drier canister sweating, 61 degree oil, CCH functional.

    Exv wouldn't seat properly and allowed liquid refrigerant to migrate back to the compressor.

    Put new valves on that Chiller 2 weeks ago.

    I've never had a CCH heater go out on any of my RTAAs

  8. #8
    Join Date
    Apr 2012
    Location
    Paper Street Soap Company
    Posts
    2,304
    But hey a extra CCH is a good way to cook fish from the inside out right ?????

    Anyone ????

  9. #9

    compressor sweating

    I installed the new cch. Came back the next morning, still sweating. had the compressor locked out all night. shut the liquid line off first, thought it was a leaking exv, didnt help. shut oil line, nothing, shut the discharge, nothing, shut the suction service valve and the sweating stopped. The chiller had not run in 20 hours, yet the compressor was sweating. I thought of a flooded evap. but even with the suction valve open there was no escape route for the refridgerant. The closing of the liquid line should eliminate the exv. leaking. in my mind. I did have 45 degree water going through the barrel, If thermal transfer was taking place the closing of the suction valve should not have made a difference, and #2 compressor should have also been sweating, in my view. Have spoken with trane in peublo, he needed some time for research. I have been through alot of the service tests, but with the unit off for 20 hours and the compressor sweating like crazy, not sure any numbers I post would be relavant, at this time.
    Any thoughts?
    thanks

  10. #10
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    2,069
    bcooling1, you should start a new thread. You've hijacked a thread about a different chiller with a different problem, that has been resolved. That could limit the number of views, and thus the amount of help that you get.

  11. #11
    Join Date
    Sep 2008
    Location
    A land down under
    Posts
    309
    Quote Originally Posted by bcooling1 View Post
    I installed the new cch. Came back the next morning, still sweating. had the compressor locked out all night. shut the liquid line off first, thought it was a leaking exv, didnt help. shut oil line, nothing, shut the discharge, nothing, shut the suction service valve and the sweating stopped. The chiller had not run in 20 hours, yet the compressor was sweating. I thought of a flooded evap. but even with the suction valve open there was no escape route for the refridgerant. The closing of the liquid line should eliminate the exv. leaking. in my mind. I did have 45 degree water going through the barrel, If thermal transfer was taking place the closing of the suction valve should not have made a difference, and #2 compressor should have also been sweating, in my view. Have spoken with trane in peublo, he needed some time for research. I have been through alot of the service tests, but with the unit off for 20 hours and the compressor sweating like crazy, not sure any numbers I post would be relavant, at this time.
    Any thoughts?
    thanks
    Model # would help further, are you sure the compressor check valve is good. Have seen circumstances where a check valve failure (which could also damage the discharge valve seat) result in a thermo-siphon effect occurring when the compressor is off and cold water circulating in the evap.
    Necessity is the mother of invention

  12. #12
    Join Date
    Mar 2007
    Posts
    3,108
    Quote Originally Posted by Screwit View Post
    Model # would help further, are you sure the compressor check valve is good. Have seen circumstances where a check valve failure (which could also damage the discharge valve seat) result in a thermo-siphon effect occurring when the compressor is off and cold water circulating in the evap.
    Good call. That's precisely the scenario I had in my mind.
    "There is no greater inequality than the equal treatment of unequals."

    -Thomas Jefferson

  13. #13
    Join Date
    Mar 2007
    Posts
    3,108
    To the OP, I have had to paint the motor terminals on RTAAs and RTACs with liquid electrical tape before. It's a good fix. It's easiest if you take the leads off the motor, just make sure you don't disturb the terminals themelves. Put the leads back in the right place or you'll be buying a new $20,000 compressor.
    "There is no greater inequality than the equal treatment of unequals."

    -Thomas Jefferson

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