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Step 9 — Adjust Evaporator-Fan Speed — Ad-
just evaporator-fan speed to meet jobsite conditions.
Table 3 shows fan rpm at motor pulley settings, Table 4
shows motor efficiencies and Table 5 gives accessory static
pressure drops. Table 6 shows motor performance. Refer to
Tables 7-14 to determine fan speed settings. Fan motor pul-
leys are factory set for speed shown in Table 1.
To change fan speed:
1. Shut off unit power supply.
2. Loosen belt by loosening fan motor mounting plate nuts
(see Fig. 34 and 35).
3. Loosen movable pulley flange setscrew (see Fig. 36).
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 maxi-
mum 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 mount-
ing plate.
To adjust belt tension (see Fig. 34 and 35):
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
one finger) and tighten mounting nuts (see Fig. 34).
Units 012,014 — Slide motor mounting plate downward
to tighten belt tension. Secure motor mounting plate nuts.
See Fig. 35.
3. Adjust bolt and nut on mounting plate to secure motor in
fixed position.
RH — Relative Humidity
Fig. 30 — Enthalpy Settings for
PARABLADE Economizer
Fig. 31 — Panels Reinstalled on Unit
Fig. 32 — Outdoor-Air Hood Installed on Unit
CONTROL
CURVE
CONTROL POINT
F (C) (APPROX)
AT 50% RH
A 73 [23]
B 70 [21]
C 67 [19]
D 63 [17]
Fig. 33 — Filter Installed on Outdoor-Air Hood
16