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  1. #1
    Join Date
    Jul 2016
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    Using zone control - Honeywell damper Normally Open

    I just had a Waterfurnace geo thermal unit installed, and the duct workers installed the Honeywell ARD dampers which are set up to power to close, and spring to open. This is the default for the Honeywell ARD, but it means a zone damper will have voltage applied to it whenever the zone is "off", or the whole system is in standby.

    This seems backwards to me, at least for our situation, but I'm open to the idea there may be reasons the Normally Open (power closed, spring open) operation is desirable.

    Using our history as a guide, one zone will be "off" 99% of the time, and would expect the overall system to be in standby the majority of the time. We may have 20 days of hot temperature each year, and 30 days where we need heat - and, within these days, the system would be in standby mode a good portion of the time. This means voltage will be needlessly applied to the dampers the majority of the time, which I would think result in earlier failures to the damper motor. If on the other hand, the dampers were set up to be Normally Closed, the voltage would be applied to the damper motors only when the heating/cooling was required.

    So, my question is whether the dampers should be set up as they are, or should they be changed to Normally Closed?

    I called Honeywell to try to find out if there are any benefits to having the dampers set to Normally Closed as default, and the fellow I talked to said the benefit would be if we had a loss of power, we could have condensate forming on the ducts if the dampers closed. I don't know if this is "real", but the answer didn't make sense to me. That would suggest that our system, when in standby and working without problems, would have a condensate problem (because the dampers are closed)

    It would be nice to get the real scoop - I would think for a residential application you'd want to only apply power to the damper when you want to open the damper.

    Any insights would be appreciated.

  2. #2
    Join Date
    Nov 2006
    Athens, Ohio
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    I think you are mistaken about the dampers.
    Here is your statement - "This is the default for the Honeywell ARD, but it means a zone damper will have voltage applied to it whenever the zone is "off", or the whole system is in standby."
    Have you looked at the dampers when the system is off or have you just assumed that they are closed?
    The zone systems we have installed as well as those we have not installed but serviced work this way - No signal is sent when the system is not running. Therefore all the dampers are open. When a zone is called, the zone panel sends a signal to close the zones which are not calling.
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