variable air valve
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variable air valve (VAV)
In an HVAC system, a control unit consisting of a metal box containing damper-position control equipment, a controller, and a sensor. The box is usually supplied with “primary” air through a duct from the main distribution system; the output delivers air to diffusers located in the space being served.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.