Carrier 50AH024 Installation, Start-Up And Service Instructions Manual page 15

carrier)
INSTALLATION
50B
BA,BB,BC024
Adjust the belts so that they can be depressed
approximately one inch with one finger midway be¬
tween the two pulleys.
FAN
WHEEL
FAN
HOUSING
DRIVE CENTER DISTANCES
Range of fan drive center distances for 50BA, BB, and
BC024 units is given in Table 3.
they are over the nearest flat surface of the
pulley hub.
3. Replace the belts and adjust the belt tension as
outlined under "Fan Belts".
MOVABLE
TABLE 3 - FAN DRIVE CENTER DISTANCES
FIG. 9 - VARIABLE PITCH PULLEY
Motor Frame
Size
Center Distance (In.)
Maximum Minimum
184
11 13/16 9 3/8
213
11 13/16 8 3/8
215 11 13/16 8 3/8
CHECK THE FAN DRIVE ADJUSTMENT
Pulleys
To adjust, loosen the setscrews in either the fan or
the motor pulleys. Align them with a straight edge or
a taut cord stretched from one pulley face to the other.
The fan motor is equipped with a variable pitch pul¬
ley. By adjustment of this pulley, the fan speed
varies the unit air quantities. To obtain the desired
fan speed (See Table 4), adjust the fan motor pulley
as follows:
ALIGN PULLEYS
Proper pulley alignment is essential. Follow the
procedure outlined below:
1. Line up pulleys by eye, and tighten screws on
fan pulley to lock it in place.
2. Slip belts on the pulleys.
3. Use the methods outlined in Fig. 10 to check
proper pulley alignment.
4. If pulleys are not in correct alignment, slide
the motor axially until the pulleys are aligned.
5. Tighten motor hold-down bolts.
FAN MOTOR LUBRICATION
Fan motors supplied with the unit have permanently
lubricated bearings and require no further lubrication.
1. Slack off on the fan belt tension by loosening
the four hold down bolts on the motor. Remove
the fan belts.
2. Loosen the setscrews in both of the movable
flanges of the pulley (Fig. 9). Screw the
movable flanges an equal amount toward the
center fixed flange to increase fan speed, and
away from the fixed flange to reduce fan speed.
Before tightening the setscrews, make certain
FAN SHAFT BEARINGS
The fan shaft bearings are permanently lubricated
ball bearing, rubber vibration mounted. They do not
require any further lubrication.
FAN SECTION ACCESS PANELS
Servicing of the fan section may be gained by remov¬
ing the front or rear panels on the fan section.
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