Every once in a while after a power outage a couple of dampers wont open. I was calling the on/off switch a disconnect. None of them have it. I was thinking about installing an on/off switch when I exercise the actuator. Usually just pulling the hot works.
That type of damper is called a combination fire/smoke damper (fsd) as opposed to a curtain-type fire damper (fd). They "fail" to the default position of closed when not energized. If there is not a dedicated fire control panel, they should be wired directly into the air-handler fan circuit,controlled with a firestat or a duct smoke detector. You then kill the FSD power by disconnecting the AHU circuit for servicing.