• Fan and motor combinations are individually tested for balance of motor capacity to fan's service requirements, ensuring proper motor loading for longer life.
• Heavy gauge Aluminum hood is die-formed for uniformity, with a rolled bead for improved strength. Hood is easily removed for access to the motor compartment.
• Motor base design transmits the motor and impeller weight to the support brackets. This prevents distortion of the exhauster base as is frequently the case with conventional exhausters that carry the weight through the orifce and housing.
• Heavy gauge corner mounted hood support brackets on PRN sizes 100-171 transmit motor and impeller weight directly to the curb. Each bracket is secured to the curb cap on both sides of the corner, providing maximum strength and rigidity.
• Forward curved impeller on the PRN080 is statically and dynamically balanced for smooth, vibration-free performance. Blades are precision die formed to insure that each blade has a uniform aerodynamic profile. Blades are secured to front and back plates by "locking tabs" that are an integral part of each blade.
• Non-overloading Aluminum airfoil impeller on the PRN sizes 100-171 is statically and dynamically balanced for smooth, vibration-free performance. Hollow airfoil blades are precision die-formed to ensure that each blade has a uniform aerodynamic profile. Blades are secured to front and back plates by "locking tabs" that are an integral part of each blade.
• Birdscreen is made of .5" x .5" galvanized hardware cloth.
• All PRN fans have motor compartments that are separated from the air being exhausted, protecting the motor from contaminants. The motor compartment is ventilated by a unique "forced air" cooling system that continuously draws fresh outside air over the motor and discharges it with the exhaust air. This continuous airflow helps protect the motor from heat build-up and extends motor life.
• Die-formed inlet orifice insures that the inlet's aerodynamic profile is maintained. The curb cap and inlet orifice are constructed of a single piece of Aluminum with continuously welded corners to assure weather tightness.
• Quality welds, heavy set rivets, and coated external fasteners assure rugged dependability and long life.
• Special design emphasis on "load bearing" stuctures, has produced a fan that is considerably lighter yet much more rigid that conventional exhausters of this type.
• Motor is factory wired with a polarized disconnect plug and socket with positive locking to prevent accidental disconnect.
• Motor is equipped with thermal overload protection and pre-lubricated ball bearings.
• Impeller, motor, and drive assembly are completely supported and cushioned by multi-directional neoprene vibration isolators.
• Solid state speed controller provides an infinite number of motor speed settings down to 50% of maximum airflow. Controller also serves as an on-off switch.
• Conduit post through the curb cap to the motor compartment is provided for wase of wiring.
• Optional backdraft damper is all Aluminum multiple blade construction with precision balanced full opening blades. Mounts inside prefabricated curb and is available as gravity operated or with an optional motorizing kit.
• Optional heavy gauge galvanized steel curb allows easy installation of the exhauster over the roof opening. Curb is insulated with 1.5" thick, fire resistant, sound absorbing glass fiber to reduce condensation and noise.