Step 9 - Adjust Evaporator-Fan Speed - Bryant DuraPac 580F Series Installation, Start-Up And Service Instructions Manual

IX. STEP 9 — ADJUST EVAPORATOR-FAN SPEED
Adjust evaporator-fan speed to meet jobsite requirements.
Table 6 shows fan rpm at motor pulley settings, Table 7
shows motor efficiencies and Table 8 provides accessory
static pressure drop information. Table 9 shows motor per-
formance. Refer to Fan Performance Tables 10-29 to deter-
mine fan speed settings. Fan motor pulleys are factory set for
speed shown in Tables 1A and 1B.
To change fan speed:
1. Shut off unit power supply and install lockout tag.
2. Loosen belt by loosening fan motor mounting plate
nuts (see Fig. 33 and 34).
3. Loosen movable pulley flange setscrew (see Fig. 35).
4. Screw movable flange toward fixed flange to increase
fan speed and away from fixed flange to decrease fan
speed. Increasing fan speed increases load on motor.
Do not exceed maximum speed specified in Tables 1A
and 1B.
5. Set movable flange at nearest flat of pulley hub and
tighten setscrew (see Tables 1A and 1B for speed
change for each full turn of pulley flange).
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.
To adjust belt tension (see Fig. 33 and 34):
1. Loosen fan motor mounting plate nuts.
2. Units 090-103 — Slide motor mounting plate away
from fan scroll for proper belt tension (
deflection with 5 to 10 lb of force) and tighten mount-
ing nuts (see Fig. 33).
Fig. 33 — Typical Belt-Drive Motor Mounting
for Sizes 090-103
1
/ -in.
2
MOTOR MOUNTING
PLATE NUTS
— 26
Units 120-151 — Slide motor mounting plate down-
ward to tighten belt tension (
5 to 10 lb of force). Secure motor mounting plate nuts.
See Fig. 34.
3. Adjust bolt and nut on mounting plate to secure
motor in fixed position.
Realign 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.
Fig. 34 — Typical Belt-Drive Motor Mounting
for Sizes 120-151
Fig. 35 — Evaporator-Fan Pulley Adjustment
—
1
/ -in. deflection with
2