A Volume Control Damper (also known as VCD or a zone damper) are specific dampers used to control the air flow in an HVAC system and it helps to adjust the air flow volume to the other parts of this HVAC system. There are automatic or manual dampers and these are always placed inside the duct itself. HVAC systems are commonly divided up into multiple zones to improve efficiency and occupant comfort.
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IRIS - Iris dampers
Galvanized steel IRIS air volume control damper of the diaphragm type with pressure measuring points