The ADV diffuser is a 24in / 600mm square ceiling VAV diffuser with built-in electric motor and controller providing VAV cooling and VAV heating. The disc damper moves open and close to meter air flow (warm or cool) into the room in response to room temperature. The damper is modulated by a robust AC motor. The electric motor, rigorously tested to provide many years of reliable service, directly drives a threaded shaft connected to the damper. Room air is sensed at the wall mounted thermostat for an accurate measurement of room temperature in both cooling and heating.