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.