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  1. #1
    Join Date
    Jul 2002
    Location
    NorthEast
    Posts
    811
    1)THis UNT 111-1 IS VERY TROUBLE SOME

    Q and A :
    Roof top
    two stage heat
    Two stage cool
    No remote setpoint (stat is malfunctioning) ?????
    BO 1 Fan- works great in Procomm and by the N2
    BO 4 and BO 5 Heat- works great in Procomm and by the N2

    BO 2 and BO 3 are cooling stages
    I cannot overide them in Procomm plus
    Even though they show they are commanded to on or off

    They do not always respond if I change the setpoint up or down
    In Commissiong mode BO 2 AND BO 2 respond only if
    I increase or decrease compressor command %


    The point attributes show they are reliable
    I cannot override them in the point attribute window either
    because override is grayed out

    Is there a a way to locate the compressor command object
    in commisioning mode and create a commandable point on the N2-BUS
    called "compressor command"

    for that matter
    how would I create an occupied unoccupied point

    Thank You

  2. #2
    Join Date
    Mar 2005
    Posts
    14
    If I remember correctly. You can not override the BO for the compressor command in an AC Unit or Roof Top unit application. I believe there is a point under the parameters menu called cooling demand or compressor demand. The point is an analog value expressed in percentage. A zero percent signal will command the compressors off, and a one hundard percent signal will command the compressors on. Be mindful that the compressors have minimum and maximum run times and maximum number of starts per hour defined in the BO point. You will need HVAC Pro to change some of these basic parameters.

    Jason in San Deigo, CA

  3. #3
    Join Date
    Mar 2005
    Posts
    14
    As for the compressors not responding to a setpoint change, it could be a number of things.
    1. Slow PI Loop
    2. Large Bias
    3. Setpoint is not going above or below the actual setpoints.
    4. Compressors locked out by to many cycles.
    5. Not enough stop time between starts on the compressor.

    Post the PRN file from HVAC Pro and we could understand the application better.

    As for adding an unoccupied setpoint, you must change the questions and answers.
    Jason in San Deigo, CA

  4. #4
    Join Date
    Jul 2002
    Location
    NorthEast
    Posts
    811
    Tommorrw I will post the PRN file

    The compressor command (%) is the point I want to

    create so that we can change the percentage and therefore command the cooling BO points

    What do they mean by Minimum Off time and Minimum On time

    It seems the same thing

    Thank You

  5. #5
    Join Date
    Mar 2005
    Posts
    14
    The Minimum on / off times are time delays. The minimum on time is the shortest time the BO will be on and the minimum off time is the shortest time the BO will be off. I was wrong by calling them minimum and maximum times. They are called minimum on/off times.
    Jason in San Deigo, CA

  6. #6
    I agree with Jason. And would also like to add that the minimum on/off times are individual for each BO (i think default @ 4 mins for compressor commands) and are accessed when you double click the actual outputs, and there is a cycles per hour attribute. The cooling % setpoints for a 2 stage unit are typically at 5% compressor command (a pseudo analog output from the cooling PID) for the 1st stage and 100% for 2nd stage. Dont forget about deadbands and the cooling bias.

    And look at your 'actual cooling setpoint' , because it will add the unreliable(ZERO) remote setpoint value to your bias to get your actual setpoint.


    --Dan, Also in San Diego

  7. #7
    Originally posted by cleancondenser
    1)THis UNT 111-1 IS VERY TROUBLE SOME


    for that matter
    how would I create an occupied unoccupied point


    You can't manually command cool/ heat stages... the root is the question you asked above... Occ/unocc is BD196, BD stands for Binary Data and is not a hardware point, that's why it doesn't show up in Q and A. Chain of command: BD196 to occupied, controller program stages heat/cool per your setpoints, once space is made occupied you over-ride by raising and lowering setpoints. Even though point shows COS nothing will happen. My first step I tell all my techs is to clear all overrides and wait if they have an ASC locked up. The only points you should over-ride are occ/unocc and setpoints! If you want I can dig out HVAC Pro users manual and give you programming steps for BD196. These steps are not in disc instructions of Hvac Pro because you are working with a legacy product. You say in other post hardware is 4 years old, which supervisory controller?

    [Edited by control_noob on 04-07-2005 at 06:40 PM]

  8. #8
    Join Date
    Jul 2002
    Location
    NorthEast
    Posts
    811
    Thank you all
    I repaired it

    I set Minimum on / off times 4 minutes and 1 minutes

    In the help section ,,which is the extent of my training,

    I found a file called paremeters ROOF TOP UNIT

    It shows every point including
    ADF
    BD
    It gives the point address THAT the UNT will recognize

    Example the compressor command % is AO 8
    heating command % is AO 7
    occupied command is BD 227
    With this info I went into Procomm then the Facilitator

    I added the POINT and it showed up in the group I wanted
    Plus it works great and can be over ride


    Mow I have another question I probabaly will make a new post

    How do I find these point parameters for the GX Tool, I print previewed the prn files but it does not indicate for example:
    The required N2 address for a PMO


    thank you for all your help

  9. #9
    Join Date
    Mar 2003
    Location
    Washington,NJ
    Posts
    504
    Hey Clean,
    Just out of curiosity, where are you located in the Northeast?

  10. #10
    Join Date
    Mar 2003
    Location
    Washington,NJ
    Posts
    504
    I missed your comments on your last post, before my last reply. Where did come up AO7,AO8 for the HTG and COMP commands? They may be ADF points but not AO's, check your PRN file for the exact point identifiers, again what part of the Northeast are you located in.

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