Variable air volume circular dampers (VAV) Circular air flow damper for VAV installations. They are used to adjust the air flow to a bypass or a room based on a 0-10v signal provided by a controller of temperature. The command signal sent by the controller position the actuator to control the flow of the need the enclosure. A foam seal inside the perimeter of the damper seals the air in case of total closure order according to EN-1751 standard. You can change a posteriori the flow Vmin & Vmax using a remote control. Galvanized steel housing, cross differential pressure measurement aluminum, connect in ABS and measuring tubes the actuator in red/blue silicone. Damper foam seal from EPDM.