49
Fig. 50 — Fan Discharge Positions, Sizes 21 and 25
START-UP
Check List
Make a walkway inside unit components to protect insulation. Re-
move all construction debris from unit interior.
Remove walkway
before starting unit.
FILTERS
Install unit filters in all filter sections.
FANS
1. Check lubrication of fan, motor bearings, and linkages.
a. Note that bearings are shipped completely full of grease
for corrosion protection and may run warm temporarily
on start-up until excess grease has discharged.
b. Hand-operate all linkages, such as damper and guide
vanes, to check for freedom of movement.
2. Check tightness of bearing setscrews or locking collars
(Fig. 51). Also, check tightness of setscrews on fan wheels
and sheaves.
3. Check tightness of fan shaft bearing mounting.
4. Recheck sheave alignment and belt tension. (Refer to Fig. 28
5. Hand turn fan to make certain fan wheel does not rub in
housing.
6. Check fan speed with a strobe-type tachometer or use the fol-
lowing formula: Obtain the motor rpm from the fan motor
nameplate and read sheave pitch diameters marked on the fan
and motor pulleys, or estimate the pitch diameters by using
the pulley outside diameters.
Fig. 51 — Fan Shaft Bearing Details
UBF
UBR
THR
THF
LEGEND
THF
—
Top Horizontal Front
THR —
Top Horizontal Rear
UBF —
Up
b
last Front
UBR —
Up
b
last Rear
SQUEEZE-TYPE LOCKING COLLAR
BEARING SETSCREW TORQUE (in.-l
b
)
BEARING HOLDDOWN BOLT TORGQUE (ft-l
b
)
39L UNIT SIZE
TORQUE
03,06,08,10,12
70
15,18,21,25
90
BOLT SIZE
TORQUE
3/8-16
30
1/2-13
63
5/8-11
100