Greenheck Fan Centrifugal Roof Downblast Exhaust Fans GB - Manual (Page 4)

Construction Features
Models G and GB
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Standard Construction Features
Wheel
An aluminum, backward-inclined, non-overloading centrifugal wheel is utilized to
generate high-efficiency and minimal sound. Wheel cones are carefully matched to the
venturi for maximum efficiency. Each wheel is robotically welded and statically and
dynamically balanced for long life and quiet operation.
Disconnect
Switch
NEMA-1 switch is factory mounted and wiring is provided from the motor as standard
(other switches are available). All wiring and electrical components comply with the
National Electrical Code
® (NEC) and are either UL Listed or Recognized.
Fan Shaft
Precisely sized, ground and polished so the first critical speed is at least 25% over
the maximum operating speed. Where the shaft makes contact with bearings, tight
tolerances result in longer bearing life.
Bearings
100% factory tested and designed specifically for air handling applications with a
minimum L
10
life in excess of 100,000 hours (L
50
life of 500,000 hours).
Motor Carefully matched to the fan load and is mounted out of the airstream.
Motor Cover
Constructed of aluminum and attached with fasteners that provide for easy removal and
access to motor compartment and drive assembly.
Motor Cooling
Cooling fins located on top of the fan wheel draw outside air through a large space
between the fan shroud and the motor cover directly into the motor compartment.
Positive motor cooling with fresh air results in maximum motor life.
Lifting Points Various lifting points are located on the drive frame and bearing plate (on select sizes).
True Vibration
Isolation Vibration isolators, with no metal-to-metal contact, support the drive assembly and
wheel for long life and quiet operation.
Drive Assembly
Belts, pulleys, and keys are oversized 150% of driven horsepower. Machined cast
pulleys are adjustable for final system balancing. Belts are static-free and oil-resistant.
Lower Windband
Heavy-gauge aluminum with formed edges for added strength and provides
weather resistance.
Curb Cap
Curb cap (with integral deep spun venturi) is constructed of aluminum and is one-piece for
a weather-tight fit.
Internal Conduit
Chase A large diameter conduit for installing electrical wiring through the curb cap into the
motor compartment.
Nameplate Permanent stamped aluminum plate for exact model and serial number identification.
Galvanized
Birdscreen
Rigid wire protects the fan discharge from birds and small objects.
Fan Shroud
One-piece, heavy-gauge aluminum with a rolled bead for extra strength directs exhaust
air downward.
Mounting Holes Curb cap has prepunched mounting holes to ensure correct attachment to the roof.
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High Wind Construction Features
Internal Supports
Heavy-gauge supports and bracing are added for additional strength to withstand
a load of 75 psf.
Reinforced
Wind Band
High wind fans include additional reinforcement for maximum strength.
Roof Curb
(page 10)
High wind-load fans are certified for use with Greenheck model GPFHL, GPFHD, GPF or
equivalent in high wind applications. Roof curbs ship separate for field installation with
attachment details provided.
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