Greenheck RBU Installation Manual

PN 455700

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Models RBU/RBUMO/RDU

Propeller Upblast Roof Fans

Installation, Operation and Maintenance Manual

Please read and save these instructions for future reference. Read carefully before attempting to assemble,
install, operate or maintain the product described. Protect yourself and others by observing all safety

Installation, Operation and Maintenance Manual

information. Failure to comply with instructions could result in personal injury and/or property damage!

Propeller Upblast Roof Fans
Direct Drive and Belt Drive

Upblast propeller fans are designed to discharge
contaminants up and away from the building for most
commercial jobs and many industrial applications.
These roof exhaust fans are produced with either
belt or direct drives and with steel or aluminum
blades. Drive frames and panels are constructed
to match the level of duty and motor size.

Inspection

Fans are thoroughly inspected and test run at the
factory prior to shipment. However, damage may
occur during handling and shipping. Consequently, it is
important that the unit be carefully inspected for visible
and concealed damage before beginning installation.
Report any damage to the shipper immediately. In
addition, assure all accessory items are accounted for.

Fig. 1

Lifting Lugs

Installation

Lifting

Attach a suitable chain or strap to the four windband
mounting brackets, which are designed to be used as
lifting lugs (Fig. 1).

Do not lift the fan by the motor, belt tube, damper
frame, windband or accessories.

Carefully lift the fan to the roof curb and install fasteners
in all holes provided in the unit base. The windband
does not need to be removed for the lifting operation.

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Propeller Upblast Roof Fans

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Electrical Connections

Before electrical connections are made, the supply

For Models RBUMO with high
temperature option - UL Listed

voltage, phase and ampere capacity must be checked
for compatibility with the fan motor. In addition, the
supply wiring must be properly fused and conform to
local and national electrical codes.

The supply wires are then connected to an optional
safety disconnect switch (if ordered) or wired directly
to the motor.

For belt drive units in Emergency Smoke Removal
installations, the electrical supply must be kept out of

the airstream. They may also require an isolated power
supply so that if power is cut to the building in the
event of a fire, the fan will continue to operate. Check
the local and national electrical codes for emergency
smoke removal fans.

Listed
Power
Ventilator
For Smoke
Control
Systems
76Y9

Models RBUMO with High Temperature Option, UL Listed
will bear the label shown above. For fan sizes 42, 48, 54 and
60 Figs. 2A and 2B apply (pg. 3)

ELECTRICAL - If fan motor is NOT thermally
protected, remote overload protection must
be installed having adequate rating as to
voltage, frequency, horsepower, and full
load current per phase. Where connected to
a circuit protected by fuses, use time delay
fuses. For supply connection use wires rated
for at least 90ºC (194ºF).

INSTALLATION - When connecting electrical
power to this fan, do not restrict motor
movement. Motor must have sufficient
movement for possible future belt or wheel
adjustment. 454975

Disconnect Wiring Options Note: Conduit and wiring by others

IMPORTANT

Disconnect Installation

RBU with NEMA-3R

Typical Installation

Wire on
inside of unit

Not recommended for high temperature exhaust

Disconnect Installation

RBUMO with NEMA-3R

High Temperature Installation

Wire on
outside of unit

Disconnect Installation

RBUMO with NEMA-3R

RBU on a GPI Curb with NEMA-3R

Propeller Upblast Roof Fans

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RBUMO with GPI and NEMA-3R

No Tray

RBUMO with GPI and NEMA-3R

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WARNING!

Disconnect and secure to the “off” position all
electrical power to the fan prior to inspection or
service.

Caution must be used when working around the
fusible link damper lifters. They may release the
dampers unexpectedly.

Models RBU, RBUMO and RDU may have fusible
link damper lifters and all RBUMO models with high
temperature options have fusible link damper lifters
under spring tension. RBUMO fans UL listed as
“Power Ventilators For Smoke Control Systems” in
sizes 42, 48, 54 and 60 have extra heavy duty fusible
link damper lifters under high spring tension that, for
safety reasons, must be pinned to prevent accidental
release. See Fig. 2 below for details on how to secure
the lifter arms.

FAILURE TO COMPLY WITH THESE SAFETY

PRECAUTIONS MAY RESULT IN SERIOUS

INJURY OR DEATH!

WARNING!

These fans have extra heavy duty fusible link damper
lifters under very high spring tension that must be
pinned so they can not be accidentally tripped when
servicing the fan. The fusible link damper lifters are
located under the butterfly damper blades. Fig. 3.
Fig. 2A shows where the two safety pins will be
located when shipped from the factory.

When maintenance is being performed on the fan, the
pins MUST be moved from Fig. 2A position to Fig. 2B
position. Fig. 2A shows where the two safety pins are
placed when the fan is in service.

Fan sizes 20, 24, 30 and 36 do not have the ability
to be pinned when servicing due to differences in
lifter designs.

IN ALL CASES, EXTREME CARE MUST BE TAKEN

WHEN WORKING AROUND THE DAMPER LIFTER

ASSEMBLIES OR SERIOUS BODILY INJURY

OR DEATH MAY RESULT.

Fig. 2

Safety Pin
Storage Location

Fig. 2A

To Prevent Closure
While Servicing Fan

Fig. 2B

Prestarting Checks

Check all fasteners and set screws for tightness.
This is especially important for bearing set screws.

The propeller should rotate freely and not rub on the fan
panel venturi. Rotation direction of the propeller should
be checked by momentarily turning the unit on. Rotation
should be in the same direction as the rotation decal
affixed to the unit or as shown in Fig. 4. For 3-phase
installations, fan rotation can be reversed by simply
interchanging any two of the three electrical leads. For
single phase installations, follow the wiring diagram
located on the motor.

Fig. 3

Butterfly
Damper
Blades

Rotation

Fig. 4

For Belt Drive Fans

The adjustable motor pulley is preset at the factory for
the specified fan RPM. Fan speed can be increased
by closing or decreased by opening the adjustable
pulley. Two or three groove variable pitch pulleys
must be adjusted an equal number of turns open. Any
increase in fan speed represents a substantial increase
in horsepower required from the motor. Always check
motor load amperage and compare to name plate
rating when changing fan speed.

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Propeller Upblast Roof Fans

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