IM-738 Page 75
With the unit running, add grease very slowly with a manual
grease gun until a slight bead of grease forms at the seal. Be
careful not to unseat the seal by over lubricating or using
excessive pressure. Bearings without grease fittings are lubri-
cated for life.
Fasteners and Setscrews
Any fan vibration has a tendency to loosen mechanical fas-
teners. A periodic inspection should include checking all fas-
teners and set screws for tightness. Particular attention should
be paid to setscrews attaching the propeller to the shaft and
the shaft to the bearings. Loose bearing set screws will lead
to premature failure of the fan shaft.
Lubrication
Refer to “Bearings” on page 74 for bearing lubrication.
Many fractional horsepower motors installed on the smaller
fans are lubricated for life and require no further attention.
Motors equipped with oil holes should be oiled in accordance
with the manufacturer's instructions printed on the motor.
Use a high grade SAE 20 machine oil and use caution not to
over lubricate.
Motors supplied with grease fittings should be greased accord-
ing to directions printed on the motor.
Removal of Dust/Dirt
Dirt clogs cooling openings on the motor housing, contami-
nates bearing lubricant and collects on propeller blades caus-
ing severe imbalance if left unchecked. The exterior surface
of the motor, fan panel and entire propeller should be thor-
oughly cleaned periodically. Use caution and do not allow
water or solvents to enter the motor or bearings. Under no
circumstances should motors or bearings be sprayed with
steam or water.
Table 20: Propeller Exhaust Fan Troubleshooting
Figure 84. Propeller Exhaust Replacement Parts List
Problem Cause Corrective Action
Reduced Airflow
System resistance is too high.
Check backdraft dampers for proper operation. Remove
obstructions in ductwork. Clean dirty filters. Check for adequate
supply for air exhaust fans or exhaust air for supply fans.
Unit running backwards. See “Prestarting Checks” on page 73
Fan speed too low. Increase fan speed
Excessive dirt on propeller. Clean propeller
Excessive Noise
Bearings
Tighten bearing collars and setscrews. Lubricate bearings.
Replace defective bearings.
V-Belt drive
Tighten pulleys on motor shaft and fan shaft. Adjust belt tension.
Align pulleys. Replace worn belts or pulleys.
Excessive vibration
Clean dirt build-up from propeller. Check all setscrews and
fasteners for tightness. Check for worn bearing. Correct propeller
imbalance. Check for loose dampers, guards or ductwork.
Defective motor Replace motor.
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1 . F a n P a n e l
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3 . D r i v e F r a m e
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8 . F a n S h a f t
9 . B e a r i n g s
1 0 . B e l t
1 1 . B e a r i n g P l a t e
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