EWC Controls 12" RD-HD Volume Control Bypass Hand Damper

The RD-HD Series of round Hand Dampers are designed for field adjustment of Differential Pressure and Velocity Control on Round Bypass Air Duct Runs. Pursuant to ACCA® Manual Zr, “A balancing hand damper should be installed in the bypass duct” for setting adequate resistance to bypass flow. The RD-HD includes a Heavy Duty Manual Quadrant allowing Easy & Accurate Field Adjustment of the Pressure Drop through the Bypass duct run. In addition, the RD-HD has a truncated blade design resulting in 70% maximum closure. This superior design ensures minimum bypass flow even if the hand damper is accidentally closed all the way. The RD-HD is designed to provide reliable and quiet Balancing Function at velocities up to 2700 feet per minute. RD-HD dampers are easy to install and adjust. The superior design insures long life with no maintenance and a 5 year warranty.