<p>Here Variable volume box details including union , strainer , balancing cock , gas valve , heating coil variable volume box , control valve , automatic balancing flow control valve , round and rectangular transition vav box also round and rectangular transition duct ,Variable air volume (VAV) systems <strong>enable energy-efficient HVAC system distribution by optimizing the amount and temperature of distributed air</strong>. Appropriate operations and maintenance (O&M) of VAV systems is necessary to optimize system performance and achieve high efficiency. VAV Zone Controller has a built-in actuator and <strong>maintains zone temperature by operating the terminal fan and regulating the flow of conditioned air into the space</strong>. Buildings with diverse loading conditions can be supported by controlling the local terminal's supplemental heat. <strong>the zone-level flow control device</strong>. It is basically a calibrated air damper with an automatic actuator. The VAV terminal unit is connected to either a local or a central control system. for more details of Variable volume box components download this file </p>