20
Step 7 — Adjust Evaporator-Fan Speed —
Ad-
just evaporator-fan speed to meet jobsite requirements.
Table 5 shows fan rpm at motor pulley settings, Table 6
shows motor efficiencies and Table 7 gives accessory static
pressure drops. Table 8 shows motor performance. Refer to
Tables 9-20 to determine fan speed settings. Fan motor pulleys
are factory set for speed shown in Table 1.
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. 43 and 44).
3. Loosen movable pulley flange setscrew (see Fig. 45).
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease fan speed.
Increasing fan speed increases load on motor. Do not ex-
ceed maximum speed specified in Table 1.
5. Set movable flange at nearest flat of pulley hub and tight-
en 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 mount-
ing plate.
To adjust belt tension (see Fig. 43 and 44):
1. Loosen fan motor mounting plate nuts.
2. Units 008,009 — Slide motor mounting plate away from
fan scroll for proper belt tension (
1
/
2
-in. deflection with
8 to 10 lbs of force) and tighten mounting nuts (see
Fig. 43).
Units 012,014 — Slide motor mounting plate downward
to tighten belt tension (
1
/
2
-in. deflection with 5 to 10 lbs
of force). Secure motor mounting plate nuts. See Fig. 44.
3. Adjust bolt and nut on mounting plate to secure motor in
fixed position.
4. Check pulley alignment and realign pulleys if necessary.
Fig. 44 — Typical Belt-Drive Motor
Mounting for Sizes 012,014
Fig. 45 — Evaporator-Fan Pulley Adjustment
MOTOR MOUNTING
PLATE NUTS
Fig. 43 — Typical Belt-Drive Motor
Mounting for Sizes 008,009
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