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  1. #1
    Join Date
    Jul 2010
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    Seekonk,Ma.
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    12

    Commercial carrier rooftop unit

    I cannot get this rooftop unit to run in an occupied mode. I am using the ccnweb to communicate with the roof top and the vvt's. If i am viewing the rooftop through the ccnweb interface,under (staus display) there is a window that says space temperature. if i force this number higher than the ccontrol setpoint then i can get this to start the indoor fans and the first stage compressor and after the time delay the second stage starts. but because i forced this number it will constntly run. What is this space temperature reading? Is it an avereage of all the space sensors or is this located in the rooftop. and secondly, what would cause this not to run in an occupied mode. never had this problem before and i am the only one that accesses these settings. No changes to the start and stop times. Help

  2. #2
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
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    3,725
    Hmmm does it have a time schedule? Is the controllers time correct? Is this a Premierlink controller?
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  3. #3
    Join Date
    Jul 2010
    Location
    Seekonk,Ma.
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    12
    no premier link, the scedule is occupied at 06:00 and unoccupied at 16:00 hours. for the space sensors and the roof top is or should be occupied 24/7.

  4. #4
    Join Date
    Jul 2010
    Location
    Seekonk,Ma.
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    12
    Are you familar with the CCNWEB. and do you know about the spacetemperature reading when logged in to the rooftop. where is this sensor or is it ann average of all the zones/VVT's in the space

  5. #5
    Join Date
    Jul 2010
    Location
    Seekonk,Ma.
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    12
    I do have 3 seperate rooftops with the premier link and a 30 ton with a comfort linkbut this one has a ccn modem board that is controling it. all of the rooftops and all of the VVT's are linked, so i access all of it from the CCNWEB.

  6. #6
    Join Date
    Jul 2010
    Location
    Seekonk,Ma.
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    12
    They all have different occupancy shedules due to the varying departments. But they all have there own occupancy number the other rooftops are fine. There is one alarm that will not clear but that shouldn't becausing this not to run in an occupied mode. I do have the stage one compressor with a small refrigerant leak which is getting changed on saturday but the low pressure switch wouldnt allow it to start either occupied or unoccupied so it isnt that. The alarm that i have says spt. 75 deg. exceeded at 79 deg. it is in the alarm history. it is not something that seems active. i think the alarm will rollout after awhile.

  7. #7
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,725
    Quote Originally Posted by freezerburn2010 View Post
    Are you familar with the CCNWEB. and do you know about the spacetemperature reading when logged in to the rooftop. where is this sensor or is it ann average of all the zones/VVT's in the space
    Are all of the units doing this ? Do you have sensors in the space? The sensor could also just be in the return since all your VVT's have sensors.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  8. #8
    Join Date
    Jul 2010
    Location
    Seekonk,Ma.
    Posts
    12
    every VVT has its own wall sensor , there is a sat in the duct and most VVT's have there own temp sensor measuring the ait at the box along with damper position wether in vent, cool or heat. i just checkr=ed the charge on that 1st stage comp. and it is fine. there is no reason why this will not run in an occupied mode. and even an unoccupied mode. I have to force the temp sensor in the rooftop ccn view page to even get it to run in an unoccupied mode. if i did not force this temp. then the mode would read off, and all the seperate zone addresses would also say off. and it would just warm up in there until i force that space temp reading. im telling it that it is warm in there because it defaults in auto to a low temperature. maybe this sensor is part of the problem, i have not found this sensor, thats why i am thinking that this reading is an average of all of the space sensors that are reporting back.????????????

  9. #9
    Join Date
    Jul 2010
    Location
    Seekonk,Ma.
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    12
    This is the only rooftop with a problem.

  10. #10
    Join Date
    Jul 2010
    Location
    Seekonk,Ma.
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    all the vvt's are working alright they open and close as the temp in the space nears its set point. but this roof top and indoor fan at minimum should always run. there is something telling this rooftop to be in the off mode. what tells it to be in the off mode. outside ambient maybe, could it be the dry bulb sensor at the economiser????. there is no real alarm that would shut this off. unless it thought it was to cold its not thwe dx lockout.????????? i will check back at this post, have a meeting at two. Thanks for your help.

  11. #11
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
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    3,725
    Have you tried cycling the power on the Plink?
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  12. #12
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
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    Are you sure the clock on the Plink had a time in the controller? There has to be something there broadcasting time to that controller.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

  13. #13
    Join Date
    Jan 2008
    Location
    Dallas ,Texas
    Posts
    3,725
    You seem to be having a controls issue I think you are wasting your time trying to find a mechanical one.
    UA 100

    It takes three people to do anything around here. Two do the work, one explains to the crowd of people who showed up when they seen smoke and flames.

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