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McQuay Chiller and JC Metasys questions

Discussion in 'Commercial' started by otto, May 12, 2016.

  1. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    So I go on a call yesterday, McQuay Model AGZ050AS42-ER10 Serial STNU020700152
    2 circuits, 2 copeland scrolls (tandems) per circuit. 4 condenser fans, 3 of them sound like chit.
    Pick up 3 motors, fuses. Done for the day.
    Back today at 07:00, 3 fans replaced by 12:00
    Circuit #2 keeps going off on low pressure. Determined bad LP transducer going into the Metasys board.
    This is a stand alone controller, no network, no interface, just a fancy staging control for the chiller.
    IMG_20160512_120417819[1].jpg IMG_20160512_120332034_HDR[1].jpg
     
  2. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    So the old sensor seems to be obsolete. I get the recommended sensor #071568521
    As I am getting ready to go pick up the new sensor, #1 starts acting up. I know, hard to believe so I get them both.
    Schrader cores under the encapsulated sensors is sweet!
    Should the new transducer have the same "profile" as the old one?
    I don't like the way circuit #1 pumps down at the termination of the call, it goes down to zero and even into a vacuum for a few seconds.

    Is there software and a cable to get to the features of this Metasys? Would it be prohibitively expensive? I would prefer to just yank that sucker out of there and rig up my own T775, LP control, two loops for the two stages, easy peasy. I would prefer to fix it right.
     

    Attached Files:

  3. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,967
    Location:
    IMT--in my truck
    Looks like an older controller, which would work with hvac pro software. Its out there on the web for free downloads if you search. The bigger issues is getting the cable to connect up. If I recall, they were about 4 or 500 bucks, and hard to get these days I think.
     
  4. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    I saw the software download this morning and even found the cable on ebay for under $100
    I am always a few versions behind the cutting edge of the BAS systems.
     
  5. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    More research this weekend. Just not sure if there is anything I can do about that pumpdown, recalibrate for the new sensor span? McQuay/Daiken so far is not returning my call from this morning.
     
  6. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,967
    Location:
    IMT--in my truck
    Around here, that's normal. Heck its normal to not get a call back for weeks, unless you NEED to buy equipment. They don't like to help others.
     
    newtech, mike1020 and otto like this.
  7. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    I have heard of others making their own cable. My toughbook CF-30 has the RS232 serial port.
     
  8. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,967
    Location:
    IMT--in my truck

    AGZ is scrolls, correct? They don't like vacuum much. Depending upon how much you like the customer, you could put a simple low pressure cutout in series with the contactor coil voltage to open at say five psig, and call it a day. When the llsv open, it would simply equalize for a few seconds, then let the pump start.
     
  9. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    I do like this customer very much and I think I will add in an extra lp control, maybe 35 psi.
    Yes, it is scrolls.
     
    mike1020 likes this.
  10. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    I am not even sure I can recalibrate for the new sensor span. Perhaps the software, cable and all that would be for naught.
     
  11. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    Like I stated earlier, I can just yank that metasys out and install a T775
     
  12. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,967
    Location:
    IMT--in my truck
    Therein lies the real problem. My guys just ran into this on an old job, trying to convert some old Honeywell stuff to a new Metasys platform. Caused me grief and money, but that's life.
     
    otto likes this.
  13. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,967
    Location:
    IMT--in my truck
    Aw hell, you could install a bunch of toggle switches too. Just make sure you series the safeties correctly. The t775 is a good control, and much simpler ot work on, so long as it can do what you need it to do.
     
  14. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    Oh well, I will worry more about it later. He called and says the system is running better than it has in years and maintaining 40 discharge temp, cycling and staging up/down. So for now I have a Trane TTA condenser to work on. No electronics, give my brain a break.
     
    ub2slo likes this.
  15. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    I already have a rough idea in my mind. Just need to put it down on paper. Thanks for the input. I will kee the updates posted.
     
  16. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    Found this: Kinda Greek to me but I do understand some of it.

    The Metasys N2 bus follows the RS-585 standard for its physical and electrical characteristics. It runs at 9600 BD, half duplex using N2+, N2-, and Ref wires. Our S4 Open appliances are pre-configured to have all Com ports operate in RS-485 mode.

    If you run any of the JCI Metasys configuration or commissioning tools HVAC Pro, GX-9100, etc. from your labtop or another Windows PC and want them to communicate the the N2 bus via their COM port you'll have to utilize either a USB to RS-485 or a RS-232 to RS-485 converter.

    We have been using RS-485 converters from B&B Electronics www.bb-elec.com to connect our PCs to the N2 bus.

    For RS-232 to RS-485 we use their model 485SD9TB

    For USB to RS-485 (N2 bus) we use their model number 485USBTB-2W

    The USB Serial Port technology has become so standardized that most manufacturers' products should work fine although the B&B products are the only ones we have tested. Note that you may have to adjust the COM port assignments for some versions of HVAC Pro because it only allows you to configure to COM1 or COM2.
     
  17. heavyevans

    heavyevans FNG

    Messages:
    1,281
    Location:
    Indy
    Like flange said you need HVAC Pro software (I can help you there), a CVTPRO cable kit or an older CBLPRO cable kit or a RS-485 converter to connect to the controller. You then need to upload the controller to see the configuration. Let me know if you want to do this.
     
  18. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
  19. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    Yes, I would like to do this. I prefer to fix this the correct way before using a work-around. If I have to spend some money there are worse things I can spend it on.
     
  20. otto

    otto Bakery Chef

    Messages:
    19,887
    Location:
    in a van down by the river
    Just checked the toughbook, it is win7 32 bit, not 64.