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  1. #14
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    Jan 2013
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    United Kingdom
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    Sounds like the internals have corroded and seized up the linkages, was the chiller offline for a long period of time, you may also find the purge unit needs looking at and worst case a tube leak and water ingress caused the corrosion.
    DC caps can fail over time and i would replace all the caps on the phase bank, they can also become stressed with time if the unit has been surging a lot, VSD's don't like surge and the rapid rises and falls in current, they are used to ramping up and down the current with speed, surge causes rapid surges in current and stresses the cap banks. VSD's also don't like dirt dust and moisture.

  2. #15
    Join Date
    Apr 2017
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    Thread Starter
    Thank you for your response

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  3. #16
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    Apr 2017
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    Thread Starter
    We're still down to 1 Chiller, it single phased last night and the control panel locked it out on manual reset. Checked it over and switched it on this morning. The PRV loads the 85% and stops due to the current limit. I have 3 - 250 ton Yorks in another building that are set at 120% for motor current. Any Suggestions?

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  4. #17
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    Jan 2013
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    United Kingdom
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    I would say that based on the Evaporator small temp difference the evaporator is short of refrigerant, whether that is due to overall refrigerant shortage or backing up of liquid in the condenser it is not clear because of two things, the drop leg temp is 'disabled' you should enable that , then you can see sub-cooling, secondly the liquid level indicator is also disabled, you should also enable that but i would do the drop leg sensor first then download a log from the Optivew via either Hyperterminal or TeraTerm using a rs 232 to usb converter.
    The trip at 120% is due to a rapid rise in Current, at or around 105 % it will close vanes to bring any motor overload under control but it will trip instantly if %current hits 120%. This will happen under surge and in your case the machine is surging due to the low refrigerant level in the evaporator, the evaporator small temp diff should be around the same as the condenser small temp diff.
    regards

  5. #18
    Join Date
    Nov 2004
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    up in the hizzy
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    raptyr, I've never been able to communicate with the machine using hyperterminal, could you share some tips? I have an old Seiko printer and that works fine printing the logs but for some reason cant do it with the laptop, havent try teraterm yet.
    There is not better place for the working men than the union! 100% UA the only HVAC union!

  6. #19
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    Jan 2013
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    Get a serial cable and an RS232 to USB converter then search on google for TeraTerm and download it to laptop then I can advise setup

  7. #20
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    Nov 2004
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    Quote Originally Posted by raptyr View Post
    Get a serial cable and an RS232 to USB converter then search on google for TeraTerm and download it to laptop then I can advise setup
    I have the cables,converters and the York instructions to connect using HT and I've tried following the steps to the letter and nothing, going download the TT software when I get home later today, thanks.
    There is not better place for the working men than the union! 100% UA the only HVAC union!

  8. #21
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    Jan 2013
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    Here you are then, make sure the printer output on the optiview panel is set to the same baud rate, i usually use 9600 for everything but sometimes if it was flaky i would set the optiview to 1200 , the TeraTerm to 1200 and go into device manager and check the port settings for the USB converter is also set to 1200
    Attached Files Attached Files

  9. #22
    Join Date
    Apr 2017
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    Thread Starter
    Thank you all for the entire conversation here it's been very valuable.

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  10. #23
    Join Date
    Apr 2012
    Location
    So.Fl. & NYC
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    hi guys, def check the purge outlet, sometimes it can get blocked up with crud, preventing the purge from venting. its going thru the motions but non-condensables have no way to be released.

  11. #24
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    Apr 2012
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    So.Fl. & NYC
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    hyper terminal on a laptop can sometimes means finding which usb port it sees on the laptop. every chiller is different, sometimes port 3 or 4 or 5. Like Raptyr said check your baud rate too. Once your in see, copy and save to word.

  12. #25
    Join Date
    Apr 2017
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    Thread Starter
    I would like to thank everybody that has contributed to this posting.

    We replaced the actuator for the prv and replace the entire linkage assembly on chiller 1 and on the other chiller here are the pictures of what arc flashed and exploded.

    Everything is up and running smoothly at this moment.

    Thanks again to everybody that helped contribute to this posting. Stay safe



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  13. #26
    Join Date
    Jan 2013
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    United Kingdom
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    The gate driver board looks very dirty, dirt , dust and moisture are a common contributor to failure, surging doesn't help either as the VSD is really designed to ramp up and down in a controlled manner, that goes out of the window when surging occurs.
    Also i did notice just now in your original photos of the PRV that someone has re-positioned the arm, notice the paint marks, I have always found this to be a warning and failure occurs after when the PRV motor over-drives the vanes and they pop the coffin lids inside.
    I have never had to adjust a vane motor arm that much and i always drive fully open and closed and check the internal limit switches.

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