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  1. #1

    York YT Chiller VFD Question

    Hello, I am wondering what the driving factors are for a York YT Chiller (VSD-YTG3A4E1-CNJ) VFD to slow down? With very low load on the chiller, the compressor VFD output remains at 60 HZ. When load continues to decrease, the chiller shuts off on low leaving water ~5 times and eventually goes into alarm.

    It seems like the compressor should begin to slow down for better load management as well as kw/ton performance?

    When the chiller is half or more loaded, I do see the compressor slow down when condensor water is cold (mid-60's). However in low load situations, it doesn't seem to matter where I put the condensor water to get a VFD reaction. I notice kw/ton get worse with warmer condensor temps as expected.

    Any feedback would be much appreciated.

    Thanks

  2. #2
    Join Date
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    sounds like a full surge map,

  3. #3
    Join Date
    Oct 2003
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    tidewater, va
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    does sound like a full surge map, take this to pro chillers forum

  4. #4
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    Quote Originally Posted by r404a View Post
    does sound like a full surge map, take this to pro chillers forum
    The OP is not a Pro Member otherwise I could move the thread there.

    Would it be better if I moved it to the open chiller forum?

  5. #5
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    yes, thanks jp

  6. #6
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  7. #7
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    You might wish to read the following. The reasons are a little too complex to state in a forum. One could say reduce lift but there comes a point where chiller design places limits. One with all the bells and whistles should, and can, run down near 10% of rated capacity.

    http://www.mcquay.com/mcquaybiz/lite.../AG_31_002.pdf

  8. #8
    Join Date
    Aug 2000
    Location
    Austell, Ga.
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    If you have ever had a leak bad enough to create s surge condition, it would load the surge mapping with incorrect mapping which would inhibit the lowering of the output frequency. I woulod advise that you clear the surge map and let the beast start over again....Assuming you do not have a problem at the present time with non-condenseables.
    Ain't "None" of us as smart as "All" of us..

  9. #9
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    richard

    doesnt york need to be called in to clear the surge map due to password?

    r404a

  10. #10
    Join Date
    Aug 2000
    Location
    Austell, Ga.
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    Quote Originally Posted by r404a View Post
    richard

    doesnt york need to be called in to clear the surge map due to password?

    r404a
    Yes they do....
    Ain't "None" of us as smart as "All" of us..

  11. #11
    Quote Originally Posted by RichardL View Post
    Yes they do....
    Thanks, I will bring this up to York. Is this map something that the chiller processor builds and adapts to ?

  12. #12
    Join Date
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    Location
    Austell, Ga.
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    Yes...It tries to find the best "Sweet Spot" for maximum eff. Sadly enough the "Sweet Spot" is very close to the surge locus. Once it detects a surge, it accelerates beyond that point and logs those conditions into memory on the ACC board. It is not uncommon for the chiller to log thousands of surges during its learning process. Sadly enough should a problem "Ever" exist with non-condenseables which could create a possible surge, the ACC board logs that possible perfect condition of vane position, motor speed etc. as a surge locus and will never accept that position again. To reset the "Surge Map", the factory must be contacted and a lengthy procedure with a York technician and the factory must be established to access the ever changing "Admin Code". Don't bother to memorize the access code he/her will use as it will only be good for a very short period of time. The "Admin Code" gives full access to all the deep logic stored in the B-Ram and could create havoc should someone mess with the core logic.
    Ain't "None" of us as smart as "All" of us..

  13. #13
    Quote Originally Posted by RichardL View Post
    Yes...It tries to find the best "Sweet Spot" for maximum eff. Sadly enough the "Sweet Spot" is very close to the surge locus. Once it detects a surge, it accelerates beyond that point and logs those conditions into memory on the ACC board. It is not uncommon for the chiller to log thousands of surges during its learning process. Sadly enough should a problem "Ever" exist with non-condenseables which could create a possible surge, the ACC board logs that possible perfect condition of vane position, motor speed etc. as a surge locus and will never accept that position again. To reset the "Surge Map", the factory must be contacted and a lengthy procedure with a York technician and the factory must be established to access the ever changing "Admin Code". Don't bother to memorize the access code he/her will use as it will only be good for a very short period of time. The "Admin Code" gives full access to all the deep logic stored in the B-Ram and could create havoc should someone mess with the core logic.
    Great information, we've had issues with flaking in the towers in the past and other things related to condenser issues. I have the advertised chiller kw/ton performance curves for these machines from manufacturer and I just am not seeing it near that in reality. I know the performance curves are for perfect conditions. I will keep you guys posted on this.

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