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  1. #1
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    York YK Millennium Chiller Stalls after pull down limit time runs out. Help!

    I need some help with a York YK chiller I cleaned the tubes, changed oil, repaired some oil leaks, oil filter, replaced PRV actuator zeroed it in and fired the unit up. Runs like a top during the pull down but after the 10 minute pull down limit the PRV opens up 100 percent and it starts a stall building to serge. The small temperature difference in the evaporator starts climbing as the PRV opens, but all the other numbers look good to me. Someone installed a Belimo actuator on the refrigeration control valve. I don't care for it being there seems like a liability.

    Oil pressure 34.5
    discharge temperature 111.4 F
    Oil sump temperature 118.2 F
    Discharge superheat 20.1 F
    0 Mils
    Full load amps 84%
    Pre Rotation vanes Position 100%

    PRV mode Auto
    Oil pump drive 40.5 Hz

    Full load amps 63%
    Inputpower 149KW
    Operating hours 56341

    Leaving chilled water 45.7F
    Return chilled water 62.4 F


    Pull down demand limit 65%
    Local motor limit 100%
    Pull down demand time 10 minutes

    Current
    A phase 232
    B phase 231A
    C phase 225A

    Delta P/P 1.99
    Surge Count 18563

    Surge margin Adjust 0.00Hz
    Stability limit 7000

    Full load amps 78%
    Current limit set point 100%
    Full load amps 357A
    Motor HP 351HP
    DC bus voltage 637v
    DC inverter link current 354A
    Internal Ambient 84F
    Heat sink 84F

    Return Condenser liquid temp 70.7F
    leaving condenser temp 84.4F
    condenser saturation 87.5F
    small temp differance 2.9F
    condenser pressure 99.5 PSIG
    sub cooling 8.0F
    Drop leg Refrigerant ??

    refrigerant level control auto
    target 11%
    position 4 %
    set point 40%
    Period 3.0seconds
    Proportion limit open 20%
    Porportion limit open 45%
    Rate limit open 10%
    Rate limit close 10%

  2. #2
    Join Date
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    Mixing oil and fire with a big spoon.
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    I noticed the Evap Small Temp Difference is missing from your list.

    your drop leg refrigerant temperature is not reading yet you show 8F subcooling?

    you also have a nearly 17F chilled water temperature drop after 10 minutes? seems high

    your liquid level valve is only 4% open? that seems very closed. this, along with the high chilled water temperature drop suggests that your liquid level valve is not open enough or you are very low on charge.
    Don't step on my favorite part of the Constitution just to point out your favorite part.

    Political Correctness is forced on you because you have forgotten decency.

    Technically speaking, they are all heat pumps.

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  4. #3
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    Thread Starter
    I cut the drop leg off my notes today on the way home I cant read it. I agree with all you said. The small difference for the evap goes up to 8.0 after the pull down bu before it goes there it is like .1-2.0 F You can watch the timer and as soon as this chiller runs the clock out it immediately start the problem.

  5. #4
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    focus on the liquid level sensor and the associated valve. you can open and close it while the chiller is not running to make sure the valve/actuator works. while running, it can be manually held open...i definitely would NOT leave it in manual, but you can force it open to make sure that all is ok after it gets past the pull down and ramps up.
    Don't step on my favorite part of the Constitution just to point out your favorite part.

    Political Correctness is forced on you because you have forgotten decency.

    Technically speaking, they are all heat pumps.

  6. #5
    Join Date
    Dec 2014
    Location
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    The Delta P/P seems high. What other numbers do you have for the evap. like small temp.
    The drop leg temp is the temp of the liquid before it gets to the liquid level valve, may be disabled on the condenser screen.
    Check pressure drops on both , evap. and condenser, get those from the sales order screen. The number listed in in feet delta , convert to psi. Use one know gage to get those numbers.
    After leak repair is the charge correct?
    Was the PRV pot zeroed or calibrated?
    After ten minutes the liquid level should have close to the set point not still at 11%.
    Did you clear the surge map to get a fresh start?
    Start with water flow and solve one issue at at time.


    Sent from my iPad using Tapatalk

  7. #6
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    Thread Starter
    I found Drop leg temp in a photo during pull down 74.3F , but during the event of stall I lost the number. I still think it is the actuator on the liquid level valve. I will return with more info.

  8. #7
    Join Date
    Dec 2014
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    It could be bad , there are three different ones that are used over the years.
    Use the raise and lower buttons to see if it moves. Verify the voltage it being sent from the I/O board.
    Check calibration of level sensor.


    Sent from my iPad using Tapatalk

  9. #8
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    Thread Starter
    That"s the plan bro. I think Chevy was talking about revisions of the same controller. Its a York thing lol.

  10. #9
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    Jan 2013
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    You need to get the liquid level in the condenser sightglass to about 1/3rd to 1/2 before you do anything else, extend the pull down time maybe 15 - 20 minutes and reduce the current limit on pulldown to around 40% . See if you build up a level in the condenser, once you have a visible 1/2 sightglass in the condenser you should also have around 6-10F subcooling, while it is stable like this check the evaporator small temp diff, should be no more than 2-2.5F, then start to slowly, manually open the vanes, keep an eye on condenser level, it should always be in the glass, if the level drops as you open the vanes and the evap small temp diff start climbing plus the sub-cooling starts to increase, you are short of gas. Let us know then we would look at next steps. Never go by nameplate charge, go by discharge superheat and sub-cooling at full load (if you can get it). Good full load would be 15F discharge superheat, 6-10F sub-cooling and Condenser/Evaporator Small Temp Diffs around 2F

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  12. #10
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    Thread Starter
    I went back today and found if I disable the liquid level valve the unit will run without the stall, but still has an issue. You guys ask for the Build
    Commissioning Date 00 000 0000
    Job name ????????
    Job location ???????????
    Model number YKDBDBH4-CNE
    Pannel serial number 00048t1200
    Chiller serial Number SNJM247490

    Design Load Evaporator
    Passes 2
    Design Working Pressure 150
    Fouling Factor .00010
    Pressure Drop 12.5
    Nozzle Arrangement In E
    Nozzel Arrangment Out B
    Leaving temperature 44.00
    Return Temperature 59.50
    GPM 700
    Tubes 181

    Condenser Design Load
    Passes 2
    Design Wiring Pressure Drop 20.9
    Nozzle Arrangement In R
    Nozzle Arrangement Out S
    Leaving Temperature 92.41
    Return temperature 82.00
    GPM 1200
    Tubes 230

    Name Plate Information
    Motor Code CN
    Volts 460
    Phases 3
    Frequency (Hz) 60
    LRA 2598
    Full Load Amps 371

    System Information
    Refrigerant R-134A
    Tons 452
    Gear Code RL
    Liquid Type water
    Brine Percent N/A
    VSD/SSS/EM VSD
    Kilowatts Input 263

    Variable speed oil pump package

    Software Versions
    Controls C.MLM.01.04.101
    BIOS C.MLM.00.01
    GUI 0.30
    SIO 0.22
    GPIC 0.04
    VSD C.VSD.01.03

    Pleases feel free to watch the video here. All my values are following the lead of these numbers for the evap and condenser alike. I used the suggested method for checking the charge and maintained liquid in the sight glass on the condenser the entire run. My guide vanes throttle with respect to the temp and pressures in the video However I have not ruled anything out here guys. Thanks for all the input so far.

    https://drive.google.com/file/d/1KEf...ew?usp=sharing

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