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  1. #1
    Join Date
    Jan 2007
    Posts
    735

    Honeywell Excel 10 stuck in Heat Mode

    I have an Excel 10 where the setpoint is 72, the room temp is 76, and the unit is stuck in heat mode and throwing the heating valve to 100% open. I cannot think of anything that would cause this unless it is some sort of a communications issue or some sort of wire possibly shorting out.

    It was doing this in the Occupied mode at the end of the day yesterday, and noticed that while it's in the Unoccupied mode right now, it's running and in full heating.

    This seems like some sort of safety override mechanism (ie: if sensor failure then go to full heat). All readings appear normal. Any thoughts?

  2. #2
    Join Date
    Jan 2007
    Posts
    735
    Here are some pics.
    Attached Images Attached Images   

  3. #3
    Join Date
    Apr 2007
    Location
    San Diego, CA
    Posts
    1,302
    nviManualMode is enabled, with the reheat valve commanded to 100%.
    Also, your occCool and occHeat setpoints are the same (68F), which violates the unoccHeat < stbyHeat < occHeat < occCool < stbyCool < occCool rule.

  4. #4
    Join Date
    Jan 2007
    Posts
    735
    Thanks digo, I wondered about the heating and cooling setpoints. The other controllers seemed to be the same way, but I went ahead and overrode them in this controller, but nothing changed. I set the nviManualMode to Auto, but nothing change. Overrode it to Disable, and everything started to work. I have released the override and all is still good.

    The only thing that puzzles me is that the unit went into Occupied mode, even though the schedule is set to unOccupied. I'm thinking it has something to do with the next TOD event, which will be tomorrow morning - which in turn will be occupied, so won't know until tomorrow evening if the unOccupied works.

    It has been a while since I have looked at this system, but do you happen to know which nvi is being linked to for the Occupancy?

    Thanks again.

  5. #5
    Join Date
    Apr 2007
    Location
    San Diego, CA
    Posts
    1,302
    nviTodEvent (currentState/nextState/Tuncos) is what's typically used for occupancy. Tuncos will gradually shift the effective setpoint from unoccupied to occupied based on the OA recovery ratios.

    Everything you need to know about that controller is found here:
    http://customer.honeywell.com/TechLi...0s/74-2958.pdf

  6. #6
    Join Date
    Jan 2007
    Posts
    735
    Tanks digo. I went that point, nviTodEvent, for testing purposes and overrode it to unOccupied and waited to see the change of state. Once it changed, I simply went back in and released the override. I just checked it this morning and it was still off and is not scheduled to come back on until tomorrow morning.

    Any thoughts on what might have caused this issue?

    Thanks for all your help.

  7. #7
    Join Date
    Apr 2007
    Location
    San Diego, CA
    Posts
    1,302
    The manual mode is what likely got it stuck in heat mode. As for the occupancy, I can't really tell. Make sure your points are bound. Does the JACE have the XL10 wizards? Does the wall sensor have a bypass push button enabled? Where are you located?

  8. #8
    Join Date
    Jan 2007
    Posts
    735
    I'm thinking the occupancy was simply stuck in it's last state because of the manual mode. I have seen this before with the other control line that we handle. When you relinquish the value, sometimes it just stays in it's present state, until the next COS.

    There are override buttons, but I do not believe they are wires in.

    I'll check on the binding.

    I sent you an email with the other question.

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