30
Fan Rotation
Correct fan rotation with respect to fan outlet is shown in Fig. 25.
To reverse the direction of rotation of a 3-phase fan motor, reverse
any 2 of the power leads. Refer to the connection diagram on the
inside of motor terminal box cover for proper reversing procedure
of a single-phase motor.
Fig. 25 — Fan Rotation
Fan Pulley Alignment
Align as follows:
1. Loosen setscrews on pulleys.
2. Align pulleys visually and tighten setscrews on fan pulley to
lock it in place.
3. Use the methods shown in Fig. 26 to check proper pulley
alignment.
Fig. 26 — Fan Pulley Adjustments
4. If pulleys are not in correct alignment, loosen the motor hold
-
down bolts and slide the motor axially until the pulleys are
aligned.
5. Tighten motor holddown bolts.
Pulley and Drive Adjustment
To obtain desired fan speed, refer to the fan motor, drive data and
performance data in Tables 18-42 and adjust fan motor pulley as
follows:
1. Remove belt from fan motor pulley after loosening motor
from motor base.
2. Loosen setscrew in moveable flange of pulley. Screw move
-
able flange toward fixed flange to increase the fan speed and
away from fixed flange to reduce speed. Before tightening
setscrew, make certain that setscrew is over nearest flat sur
-
face of pulley hub. (See Fig. 26.)
Condensate Drains
Keep condensate drains free of dirt and foreign matter.
Return-Air Filters
Refer to Replacing Filters section on page 42 for filter accessibili
-
ty and removal. Replace with clean filters of the sizes listed in
Chilled Water Coil Freeze Protection
Shut off water supply to unit. Remove side panel of unit and
remove vent and drain plugs in top and bottom of coil header.
Drain coil and blow out remaining water. Reinstall plugs and side
panel. Alternative freeze protection methods follow:
• Circulate hot water within the water coil’s supply main or
supplementary space heating.
• Close off supply lines to unit and open a union or field-
supplied drain valve in the return line.
• After draining as much water as possible from coils, add
sufficient antifreeze to prevent residual water in the coil
from freezing.
• Add a sufficient quantity of non-corrosive antifreeze to the
entire system to prevent all water within the system from
freezing.
Coil Removal
Remove unit panels and corner posts as required. Disconnect coil
connections and remove fastening screws. Remove coil through
end or side sections of unit.
Cleaning Cooling Coil
Remove return-air filters. Remove any heavy dirt that may have
accumulated on underside of coil. Coil can be cleaned more easily
with a stiff brush, vacuum cleaner, or compressed air when coil is
dry. If coil is wet or if water is to be used for cleaning, guard
against splashing water on electrical components or damaging
surrounding area. Clean coil baffles as applicable and check for
tight fit to be sure air does not bypass coil.
Cleaning Insulation
The insulation contains an immobilized antimicrobial agent that
helps prevent the growth of bacteria and fungi. Clean the inner
surface of the insulation according to the separate maintenance
instructions shipped with the unit.
Air
Discharge
Cutoff
Plate
Fan
Wheel
Fan
Housing
Adjustable Flanges
Setscrews
Straight Edge Must
Be Parallel
With Belt
Fixed Flanges
Two Grooves
Single Groove
Motor and Fan Shafts
Must Be Parallel
Pulleys
Setscrews
CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution could cause equipment damage.
Increasing fan speed produces a greater load on motor.
Do not exceed rated capacity of motor.
IMPORTANT: Draining from return line will not completely
drain water from coils.
