User`s manual

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26
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III. INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS
Adjust evaporator-fan RPM to meet jobsite conditions and
temperature rise in Table 1. Table 8 shows fan rpm at motor
pulley settings. Table 9 shows motor performance. Refer to
Tables 10-17 to determine fan speed settings.
A. Belt Drive Motors
Fan motor pulleys are factory set for speed shown in Table 1.
NOTE: Before adjusting fan speed, make sure the new fan
speed will provide an air-temperature rise range as shown in
Table 1.
To change fan speed:
1. Shut off unit power supply and tag disconnect.
2. Loosen belt by loosening fan motor mounting nuts.
See Fig. 47 and 48.
3. Loosen movable pulley flange setscrew (see Fig. 49).
4. Screw movable flange toward fixed flange to increase
RPM and away from fixed flange to decrease RPM.
Increasing fan speed increases load on motor. Do not
exceed maximum speed specified in Table 1.
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.)
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.
To adjust belt tension:
1. Loosen fan-motor nuts.
2. Sizes 090, 102:
Slide motor mounting plate away from fan scroll for
proper belt tension (
1
/
2
-in. deflection with 8 to 10 lb.
of force).
Sizes 120, 150
:
Slide motor mounting plate downward to tighten belt
tension (
1
/
2
-in. deflection with 8 to 10 lb. of force).
3. Tighten nuts.
4. Adjust bolt and nut on motor to secure motor in fixed
position.
5. Verify pulleys are in correct alignment.
Table 8 — Fan Rpm at Motor Pulley Settings*
*Approximate rpm shown.
†Indicates standard motor and drive.
**Indicates alternate drive.
††Indicates alternate motor and drive.
CAUTION: For cooling operation, the recom-
mended airflow is 300 to 500 cfm per each 12,000 Btuh
of rated cooling capacity. For heating operation, the air-
flow must produce a temperature rise that falls within
the range stamped on the unit rating plate.
UNIT
580D
MOTOR PULLEY TURNS OPEN
0 11223344556
090†
840 815 790 765 740 715 690 665 640 615 590 ——
090**
935 910 885 860 835 810 785 760 735 710 685 ——
102†
935 910 885 860 835 810 785 760 735 710 685 ——
120†
935 910 885 860 835 810 785 760 735 710 685 ——
120††
1085 1060 1035 1010 985 960 935 910 885 860 835 ——
150†
1080 1060 1035 1015 990 970 950 925 905 880 860 ——
150††
1260 1220 1185 1155 1130 1100 1075 1045 1015 990 960 930 900
Fig. 47 — Typical Belt-Drive Motor Mounting
for Sizes 090, 102
Fig. 48 — Typical Belt-Drive Motor Mounting
for Sizes 102, 150
Fig. 49 — Evaporator-Fan Pulley Adjustment