SPAD Gen. 3 – Static Pressure Adjustable Mechanical Bypass Damper

Introduction

The Static Pressure Adjustable Damper, Model SPAD, is a single blade, counter-balancing spring damper, that operates on air pressure in order to control the flow of by-pass air on a zoned system. The SPAD utilizes an adjustable knob/blade to maintain the correct amount of pressure in the duct system. The SPAD allows for setpoints between 0.3 inches W.C. of pressure to 0.8 inch W.C.

As zone dampers close off air to a number of zones, the supply air pressure in the duct system will increase. This increase in air pressure can increase the noise level and reduce the flow of conditioned air through the HVAC Unit. The SPAD operates similar to the SPRD in that it helps maintain a constant air pressure in the duct system. However, the SPAD utilizes minimum setpoints for the blade to respond to air pressure. This reduces buildup of pressure within the supply and also helps reduce the noise that is caused by these high air pressures and velocities, as well as maintains a constant volume of air (CFM) through the duct system. Maintaining a constant volume of air through the HVAC System keeps the efficiency of the system at its maximum. The SPAD is available in round sizes only. The chart below lists the available sizes of SPADs and their recommended CFM capacities.