Bryant DURAPAC PLUS 581A Installation And Service Instructions Manual page 39

IV. EVAPORATOR FAN PERFORMANCE ADJUSTMENT
(Fig. 32 and 33)
Fan motor pulleys are factory set for speed shown in Table 1.
To change fan speeds:
1. Shut off unit power supply.
2. Loosen nuts on the 4 carriage bolts in the mounting
base. Using adjusting bolts and plate, slide motor and
remove belt.
3. Loosen movable-pulley flange setscrew (see Fig. 33).
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed maximum speed specified in Table 1.
See Table 24 for air quantity limits.
5. Set movable flange at nearest keyway of pulley hub
and tighten setscrew. (See Table 1 for speed change
for each full turn of pulley flange.)
6. Replace and tighten belts (see Belt Tension Adjust-
ment section below).
7. Restore power to unit.
To align fan and motor pulleys:
1. Loosen fan pulley setscrews.
2. Slide fan pulley along fan shaft.
3. Make angular alignment by loosening motor from
mounting plate.
V. BELT TENSION ADJUSTMENT
To adjust belt tension:
1. Turn off unit power.
2. Slide out fan deck to service position as shown in Evap-
orator Fan Service and Replacement section above.
3. Loosen fan motor bolts.
4. Move motor mounting plate to adjust to proper belt
tension. See Table 30. Motor adjuster bolts may be
used to tighten belts. See Fig. 32.
5. Check for proper belt alignment. Adjust if necessary.
6. Tighten motor mounting plate bolts to lock motor in
proper position.
7. Return fan deck back into operating position.
8. Restore power to unit.
Table 30 — Belt Tension Adjustment
581A
UNIT VOLTAGE
SIZE
Low Vert
230 4.9
210 460 4.9
575 3.9
230 5.1
240 460 5.1
575 5.1
230 5.9
300 460 5.9
575 5.9
LEGEND
Horz — Horizontal
Vert — Vertical
BELT TENSION (lb)
Fan Type
High Vert Low Horz High Horz
5.1 4.7 5.0
5.1 4.7 5.0
5.2 3.8 4.7
5.6 5.0 5.5
5.6 5.0 5.5
5.6 5.0 5.5
4.5 5.9 4.5
4.5 5.9 4.5
4.5 5.9 4.5
VI. CONDENSER-FAN ADJUSTMENT (Fig. 34)
1. Shut off unit power supply.
2. Remove condenser-fan assembly (grille, motor, motor
cover, and fan) and loosen fan hub setscrews.
3. Adjust fan height as shown in Fig. 34.
4. Tighten setscrews and replace condenser-fan assembly.
5. Turn on power to unit.
FAN
PULLEY
Fig. 32 — Evaporator-Fan Motor Adjustment
Fig. 33 — Evaporator-Fan Alignment and Adjustment
Fig. 34 — Condenser-Fan Adjustment
— 39 —
MOTOR
PULLEY
(HIDDEN)
MOTOR
MOUNTING
BASE
SLIDE-OUT
FAN DECK