Jim wrote:
.. how can the
upstairs temp be exceeding its set point? Does the damper never really
fully close on the 'non-calling' zone? Is this thing wired and/or
operating correctly? Zone control is EWC Ultra Zone. Thanks!..

Hot air rises. In the summer if you have AC working on the same system,
you may find that the lower floor is seldom active.

It also should be noted that in most situations using dampers, they are
seldom totally sealed.

--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math