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Fig. 21 — Fan Shaft, Bearings, and Fan Wheel
(Typical)
Centering Fan Wheel
If fan and fan shaft assembly are not properly centered,
blades may scrape against the blower side scroll plate or
may create an objectionable whistling noise. It may be nec-
essary to adjust individual fan wheels or move entire fan
shaft. See the following 2 sections.
Fan Shaft Position Adjustment
Loosen setscrew or locking collar of each fan shaft bearing.
Slide shaft into correct position and replace locking collar.
(See Fig. 22). To replace locking collar, push collar up
against inner face of bearing. Turn collar in direction of fan
rotation until tight, and tighten setscrew. Tightening locking
collar in direction of fan rotation results in further tightening
of collar should setscrew work itself loose.
FAS-FHS-072-180-01SI Rev. A
Individual Fan Wheel Adjustment
Loosen the 2 locking bolts holding the fan wheel hub to
shaft. (See Fig. 21.) Position fan wheel in center of the fan
housing and tighten locking bolts. Clearance between
wheel and housing should be the same on both sides.
Fan Belts
Motor mounting plate and motor support angles are slotted
to permit both vertical and horizontal adjustment. Adjust
belt(s) for correct deflection by loosening motor plate
mounting bolts, moving motor/plate assembly forward or
back, and re-tightening bolts. Press down on belt with one
finger midway between fan and motor pulleys to check
deflection. For units with motor sizes up to and including
3.7 Hp (2.76 kW), correct deflection is 3/16 in. (4.8 mm). For
larger motor sizes, correct deflection is 1/8 in. (3.2 mm).
(See Fig. 23.)
If complete belt replacement is required during servicing,
loosen the motor plate mounting bolts (Fig. 23), move
motor/plate assembly towards fan pulley, and pull belt(s) off
pulleys. Reverse the procedure with new bolts and readjust
deflection.
Fig. 23 — Fan Motor Mounting
Specifications subject to change without notice.
Fig. 22 — Fan Shaft Bearing
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