I have a Carrier Comfort Maker zone system that was installed in my house when it was built in 1997. These are the three wire power open / power close style dampers. When I had the system replaced, I replaced the zone board with a Honeywell HZ432 to accomodate the dual fuel setup, but we left the existing dampers.

In any case, I went into the attic today and heard one of the dampers making kind of a clicking or chirping noise. The system was not running, and hadn't been running for a while.

When I put my finger on the motors in each of the dampers, it felt like they were both running. The noisy one got quiet after I touched the motor. My question is this... do the damper motors continue to run all of the time, or should they time out or have a limit switch, so that the motor isn't running while the system is off or after the damper is in position?