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  1. #1
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    Apr 2011
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    Louisville
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    Confused RTAC225 Starter Transition faults--pulling out hair

    This chiller had same fault on both circuits. Changing out the auxiliaries on contactors worked for one of them. The#2 circuit has continued to trip intfaultermittently--starter transition fault. Sometimes it does fine. Contactors seem OK. Has anybody seen an intermittent problem with the starter module? I do not want my customer to lose faith. I don't want to be a parts changer. Advice would be greatly appreciated.

  2. #2
    Join Date
    Jul 2007
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    The Hot South
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    Talking

    Quote Originally Posted by jimtwalkermech View Post
    This chiller had same fault on both circuits. Changing out the auxiliaries on contactors worked for one of them. The#2 circuit has continued to trip intfaultermittently--starter transition fault. Sometimes it does fine. Contactors seem OK. Has anybody seen an intermittent problem with the starter module? I do not want my customer to lose faith. I don't want to be a parts changer. Advice would be greatly appreciated.
    How old is this chiller? Does it have the Benshaw or Cutler Hammer contractors? Is it Y Delta?

    Also, I have to say, I've never heard the term intfaultermittently before.

  3. #3
    Join Date
    Jun 2010
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    U.A. (upper Alabama)
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    Quote Originally Posted by R123 View Post
    How old is this chiller? Does it have the Benshaw or Cutler Hammer contractors? Is it Y Delta?

    Also, I have to say, I've never heard the term intfaultermittently before.
    My bet is on the Benshaw. Replace them with Cutler Hammer and appropriate auxillaries, end of problems.

  4. #4
    Join Date
    Jul 2009
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    In a mechanical room....
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    I have had them trip intermittently, bad aux or loose wire, FYI get the oem aux not just some junk you had laying around on a shelf.
    “It takes courage to grow up and turn out to be who you really are.”

    - E.E. Cummings

  5. #5
    Join Date
    Apr 2011
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    Louisville
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    "Interfaultmittently" ??? I don't know where that word came from but it seems like a good word to use for some of these "loose wire/bad connection" faults. I was on my phone and it edits itself a little too much. I changed the auxiliaries with factory parts and did not cure the problem. I am going to pull the contactors apart and clean them and cut the wire ties to access the wire all the way to starter module.

    I guess nobody has ever had any intermittent module problems. We are so swamped with work, I'm having a hard time getting on the job. I have a tear down in the middle of summer, screw compressor change out and all kinds of crap. Busiest summer ever.

  6. #6
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    You never answered if its a Benshaw or Cutler Hammer starter and if its Y-Delta or Across the Line. I can probably help you if you answer this question.

  7. #7
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    Apr 2011
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    Louisville
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    It is a Benshaw Y-Delta.

  8. #8
    Join Date
    Jul 2007
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    The Hot South
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    Benshaw had a problem with the mechanical interlock between the run and shorting contactor binding up causing this fault. It was corrected by making a stronger coil. I fought with this problem for weeks when they first came out and before the cause of the problem was identified. My immediate fix at the time was to put a drop of greasless lubricant in the interlock to smooth it out and the problem was solved. The proper way to fix it is to replace the contactors (now that they have the stronger coils).

  9. #9
    Join Date
    Mar 2011
    Posts
    258
    Along the lines of the "stronger coils" we had a bunch of Benshaw starters with fancy A/C to D/C coils. The coils would pull in then "chatter" and the chiller would trip on starter fault. We replaced all the A/C to D/C coils with straight A/C 120V coils and that cured the problem.

  10. #10
    Join Date
    Mar 2004
    Location
    ottawa canada
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    2,052
    Quote Originally Posted by R123 View Post
    Benshaw had a problem with the mechanical interlock between the run and shorting contactor binding up causing this fault. It was corrected by making a stronger coil. I fought with this problem for weeks when they first came out and before the cause of the problem was identified. My immediate fix at the time was to put a drop of greasless lubricant in the interlock to smooth it out and the problem was solved. The proper way to fix it is to replace the contactors (now that they have the stronger coils).
    I had excatly this problem on a new RTHD start up . Took the mechanical interlock apart ,cleaned it , squirted it with Jig-a-Loo and bingo all good and never had a problem since and that was 3yrs ago .
    The 64 roars to life Whoo hoo ...shes a rolling chassis .
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  11. #11
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    Quote Originally Posted by graham View Post
    I had excatly this problem on a new RTHD start up . Took the mechanical interlock apart ,cleaned it , squirted it with Jig-a-Loo and bingo all good and never had a problem since and that was 3yrs ago .
    Yep....that is EXACTLY what I did and it was also 3 years ago. We had 12 RTAC500's at a data center and they were ALL acting up. That's 48 compressors. I went through all 48 starters, took apart the interlock, squirted the lube in there and never went back for that problem since.

  12. #12
    Quote Originally Posted by R123 View Post
    Yep....that is EXACTLY what I did and it was also 3 years ago. We had 12 RTAC500's at a data center and they were ALL acting up. That's 48 compressors. I went through all 48 starters, took apart the interlock, squirted the lube in there and never went back for that problem since.


    Data Centers require high maintenance that is why we all have to practice the information about HVAC.

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