Spun aluminum downblast exhaust fans shall be direct drive type.. These fans are specifically designed for roof mounted applications exhausting relatively clean air.. Performance capabilities range up to 6,640 cfm (11,281 m3/hr) and 1 in. wg (249 Pa) of static pressure.. The maximum continuous operating temperature shall be 180°F (82°C).. Model G fans are available in 20 sizes with nominal wheel diameters ranging from 7 to 20 inches (178 to 457 mm) (060-203 unit sizes).
Each fan shall bear a permanently affixed manufacturer’s engraved metal nameplate containing the model number and individual serial number..
All fans shall bear the AMCA Sound and Air Performance seal..
The fan wheel shall be centrifugal non-overloading backward-inclined, constructed of aluminum and shall include a wheel cone carefully matched to the inlet cone for precise running tolerances.. Wheels shall be statically and dynamically balanced in accordance to AMCA Standard 204-05..
For models G-060 through G-095, fan shall have sleeve bearing motors, carefully matched to the fan load, and furnished at specified voltage, phase and enclosure.. For models G-097 through G-203, motors shall be heavy-duty ball bearing type, carefully matched to the fan load, and furnished at the specified voltage, phase and enclosure.. Models G-060 through G-095 have three-speed motors as standard.. Motors shall be mounted on true vibration isolators, out of the airstream.. Fresh air for motor cooling shall be drawn into the motor compartment from an area free of discharge contaminants.. Motors shall be readily accessible for maintenance.. True vibration isolators shall be double-studded with no metal-to-metal contact.. Each vibration isolator shall be sized to match the weight of each fan.
The fan housing shall consist of the motor cover, shroud, curb cap and lower windband, and shall be constructed of heavy-gauge aluminum.. Housing shall have a rigid internal support structure and leakproof design.. The fan shroud shall be one piece with a rolled bead for extra strength which directs exhaust air downward. The lower windband shall be one piece with formed edges for added strength and the curb cap shall include prepunched mounting holes to ensure correct attachment..
A disconnect switch is a positive electrical shutoff and shall be wired from the fan motor to a junction box installed within the motor compartment. Factory standard shall be a NEMA-1 disconnect switch with other NEMA rated options also available. Disconnect switches shall be factory mounted and/ or shipped loose for field mounting..
Options and accessories shall include: curb extension, curb seal, dampers, finishes, hinge kit, hinge base, pressure probe, roof curbs, and tie-down points..
Fans shall be model G as manufactured by Greenheck Fan Corporation of Schofield, Wisconsin, USA..
