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  1. #1
    Join Date
    Jun 2008
    Location
    Jacksonville, Florida area
    Posts
    59

    Carrier Comfort Network Question

    I am involved with a CCN system and one of the AC systems connected to it is a six zone VAV. The AHU fan for the VAV system is always ON. I removed all schedules to be sure a schedule wasn't causing it to run. When I look at the status page, it is not forced on, although I can't change the run status to AUTO either. When I attempt to do this I get a "Force/Auto error: insufficient priority" . Any ideas?

  2. #2
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    If you removed all the schedules I am assuming it is in 24/7/365 occupied mode

    Which would run the fan all the time ,for heat , cool , or ventilation mode at the individual vav's

    If any vav or ah is in occupied mode I believe the fan will run .

    If all items ,per schedule or force mode ,is in un-occupied and the unoccupied setpoints are satisfied I believe the fan should be off . If room conditions drift above / below unocc setpoints system will start ,satisfy, then shut back down.

    Did I say that right ?
    mikeacman

  3. #3
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    Maybe post this in the controls forum as well...
    mikeacman

  4. #4
    Join Date
    Jun 2008
    Location
    Jacksonville, Florida area
    Posts
    59
    Mike,
    There were a bunch of schedules that I removed, which I thought may have been keeping the fan running. When I removed them the fan didn't turn off.

    All zones are above their heating unoccupied and below their cooling unoccupied set points.

    You mentioned vantilation mode, where is this set up in the AHU or at each VAV?

  5. #5
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    Vent mode is during occupied ,when not heating or cooling it is in ventilation mode which delivers minimal air flow for ,well ventilation ,indoor air quality requirements when bldg is occupied.

    The biggest ? Is

    Is everything going to unoccupied?

    If not your fan is gonna run

    Occupied =fan on
    Unoccupied and set points satisfied = fan off

    That is what I would.look for first.
    mikeacman

  6. #6
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    Every device has somewhere in its menu to see if it's occupied or unoccupied
    mikeacman

  7. #7
    Join Date
    Jun 2008
    Location
    Jacksonville, Florida area
    Posts
    59
    When I look at the status page for each VAV it gives the "terminal mode"- either heat, vent or cool. I don't see anywhere that there is reference to occupied/unoccupied.

    Three of the zones say "vent" mode, although they are controlling to an 85 degree set point (unoccupied cool set point) and it is between 73.2 - 74.1 in the spaces, so I assume they can not cause the AHU to run.

    The other three zones say "heat" mode, and they are controlling to 60 degree set point (unoccupied heat set point) and it is between 71.9 - 72.5 in those spaces.

    I don't truly understand why some of them are in vent mode and others are in heat mode either.

  8. #8
    Join Date
    May 2002
    Location
    evansville indiana
    Posts
    943
    Okay ,well that explains why your fan is on ...

    Something's amiss and I can't tell you why ,maybe you aren't logged in on a high enough level to get to the menus where you can see other details such occupied / unoccupied and configuration parameters.

    I don't want to give you any bad advice or have you running down something that isn't there .It isn't that I know and won't tell you . Its that I don't know and am going to bow out at this point.

    Where's the control guys at?
    mikeacman

  9. #9
    Join Date
    Jun 2008
    Location
    Jacksonville, Florida area
    Posts
    59
    Mike,
    I'm logged in at level 4 which I believe is the highest level.

    I can see/schedule occupied/unoccupied setpoints, just can't necessarily see a status for this.

    Thanks for your ideas.

  10. #10
    Join Date
    May 2004
    Location
    SE Pennsylvania
    Posts
    1,010
    When you removed the schedules did you download? Look in maintenance Display / OCCDEFME / OCCPC64S - occupancy supervisor. Level 5 is the highest, but 4 should be fine.

  11. #11
    Join Date
    Jun 2006
    Location
    New Jersey
    Posts
    4,340
    You have info on what kinda of system we are looking at? What kind of air source controller and terminal controller?

    To see zone terminal occupancy status.........Maintenance > ZNMAINT
    To see air source occupancy and mode status..........Maintenance > LINKMNT

    Also, you can't force(override) fan status........it's a read only point. Also, there is no "Auto" mode for the fan.......it's either "on" or "off".

  12. #12
    Join Date
    Jun 2008
    Location
    Jacksonville, Florida area
    Posts
    59
    You asked if I "download"ed after removing the schedules. There is and "Apply" button on the schedule screen, is that what you are referring to?

  13. #13
    Join Date
    Jun 2008
    Location
    Jacksonville, Florida area
    Posts
    59
    The air source controller is a 33CSPREMLK PremierLink controller and the terminal controllers are 33ZCVVTZC 3V Controllers.

    So in the ZNMAINT section I see the first line is "Occupied" on each VAV, I assume when the "Value" says Yes then that zone is occupied, which will force the fan on, correct? If all zones "Value" show No, then the fan should turn off?

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