Greenheck’s new Model APD plenum fan features a direct drive fan with the wheel connected to the motor shaft. With no fan shaft bearings or belts to maintain, the company says its Model APD eliminates the cost and maintenance associated with traditional belt drive plenum fans. The plenum fan is ideal for an array of applications in air handler retrofits or when pressurizing a plenum room. When combined with a VFD, officials said air volumes can easily be matched to changing building requirements or overcome increased pressures from dirty filters. Model APD offers an operating range up to 18,000 cfm and external static pressure up to 10 in. wg. The model is constructed from a formed and bolted galvanized steel frame with a welded and coated 7-bladed, backward-curved steel wheel, and can be used as a stand-alone single fan or in parallel fan array applications.