Belt And Bearing Maintenance - Greenheck DFD Series Installation, Operation And Maintenance Manual

3. Install the two bushing socket head cap screws
into the aligned holes by hand (or without excessive
torque) until the heads of the socket head cap
screws are seated against the mating surface.
4. Adjust the height of the wheel in the fan relative to
the inlet venturi then tighten the two socket head
cap screws an eighth turn at a time in an alternating
fashion and to a torque of 10 ft-lbs.

Belt and Bearing Maintenance

1. Belts tend to stretch after a period of time. They
should be checked periodically for wear and
tightness. When replacing belts, use the same type
as supplied with the unit.
2. Matched belts should always be used on units with
multi-groove pulleys.
3. For belt replacement, loosen tensioning device
enough to allow removal of the belt by hand.
4. Once installed, adjust belts as shown in
"Pre-Starting Checks."
5. To ensure tightness, check pulley setscrews. Proper
keys must be in keyways.
6. Fan RPM should not be readjusted. Only use
pulleys of identical size and type when replacing
pulleys.
7. Shaft bearings can be classified in two groups:
relubricating and non-relubricating. All non-
relubricating bearings on belt drive fans are factory
lubricated and require no further lubrication under
normal use (between -20º to 180ºF (-29º to 82ºC) in
a relatively clean environment).
8. On belt drive fans, the standard cast pillow block
bearings are factory lubricated and are provided
with external grease fittings. Annual lubrication
is recommended, or more frequently if needed,
see Table 1. Do not over-grease. Use only one or
two shots of lubricant with a hand gun. Maximum
hand gun rating is 40 psi. Rotate bearings during
lubrication where good safety practice permits.
Caution should be employed to prevent over
packing or contamination.
9. Units installed in hot, humid or dirty locations
should be equipped with special bearings. These
bearings will require frequent lubrication. Caution
should be employed to prevent over packing or
contamination.
10. Grease fittings should be wiped clean. The unit
should be in operation while lubricating bearings.
Extreme care should be used around moving parts.
11. Grease should be pumped in very slowly until a
slight bead forms around the seal. A high grade
lithium base grease should be used (see Table 2).
12. During the first few months of operation, check
bearing set screws periodically to ensure tightness.
13. 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.
10 Upblast Centrifugal Roof Exhaust
Recommended Bearing Lubrication
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 in Table 2
may be used.
Table 1: Suggested Fan Bearing Lubrication Intervals
Interval
(months)
Heavy duty in dirty, dusty locations; high ambient
1 to 3
temperatures; moisture laden atmosphere; vibration.
12 to 24 hours per day, heavy duty, or if moisture is
3 to 6
present
8 to 16 hours per day in clean, relatively dry
6 to 12
atmosphere
12 to 18 Infrequent operation or light duty in clean atmosphere
Table 2: Grease Manufacturers
Manufacturer
U.S. Electric Motors
Chevron U.S.A. Inc
Mobil Oil Corporation
Texaco, Inc.
Amoco Oil Co.
Exxon
Shell
Type of Service
Grease (NLGI #2)
Grease No. 83343
Chevron SRI Grease #2
Mobilith
Mobil 532
Premium BRB #2
Texaco Multifak #2
Rykon Premium #2
Unirex N2
B Shell Alvania #2
®