7
Model H-G/H-GB Centrifugal Roof Exhaust Fan
Table 3: Grease Manufactures
Manufacturer
Grease (NLGI #)
U.S. Electric Motors
Grease No. 83343
Chevron U.S.A. Inc
Chevron SRI Grease #2
Mobil Oil Corporation
Mobilith
Mobil 532
Texaco, Inc.
Premium BRB #2
Texaco Multifak #2
Amoco Oil Co.
Rykon Premium #2
Exxon
Unirex N2
Shell
B Shell Alvania #2
Table 2: Suggested Fan Bearing Greasing Intervals
Interval
(months)
Type of Service
to 3
Heavy duty in dirty, dusty locations; high ambient
temperatures; moisture laden atmosphere;
vibration.
3 to 6
12 to 24 hours per day, heavy duty, or if moisture
is present
6 to
8 to 16 hours per day in clean, relatively dry
atmosphere
to 8
Infrequent operation or light duty in clean
atmosphere
8. Grease should be pumped in very slowly until a slight
bead forms around the seal. A high grade lithium
base grease should be used.
9. To ensure tightness check pulley setscrews. Proper
keys must be in keyways.
10. Fan RPM should not be readjusted. Only use pulleys
of identical size and type when replacing pulleys.
11. During the first few months of operation check
bearing set screws periodically to ensure tightness.
12. If unit is to be left idle for an extended period,
remove belts and store in a cool, dry place to avoid
premature belt failure.
Recommended Relubrication Frequency in
Months
NOTE: If unusual environment conditions exist (extreme
temperature, moisture or contaminants) more frequent
lubrication is required.
A good quality lithium base grease, conforming to NLGI
Grade 2 consistency, such as those listed here may be
used.
Dampers must open
fully. Use motorized
dampers in low airflow
applications to reduce
losses.
Avoid sharp turns or
entrance conditions
which cause uneven
flow. Use turning vanes
in elbows to reduce
adverse effects.
Provide uniform
airflow at fan inlet
to assure optimum
performance.
Provide uniform airflow at fan inlet
and through the damper to assure
optimum performance. The curb cap
should be three wheel diameters
from the radius. Use turning vanes in
duct when possible.
Fan Inlet Connections
In order to assure proper fan performance, caution must be exercised in fan placement and connection to the
ventilation system. Obstructions, transitions, poorly designed elbows, improperly selected dampers, etc, can cause
reduced performance, excessive noise and increased mechanical stress. For performance to be as published, the
system must provide uniform and stable airflow into the fan.
Poor
Good
Poor
Good
Poor
Good
Poor
Good
