Carrier 50BA - Manual (Page 15)

6. Check Pulley Alignment and Belt Tension
Adjustment as described below.
7. Check fan operation. Repeat above procedure
as required.
PULLEY ALIGNMENT — Loosen fan motor
pulley setscrews and slide fan pulley along fan
shaft. Make angular alignment by loosening motor
from mounting bracket. See Fig. 26.
BELT TENSION ADJUSTMENT Loosen fan
motor from mounting bracket. Do not loosen
motor mounting bracket from unit. Move fan
motor until proper belt tension is achieved
(approximately 1-in. deflection with one finger at
midpoint of belt span).
Lubrication — Fan motor bearings are factory
lubricated and will need no lubrication for the first
5 years (3 years at continuous service or exces­
sively dirty conditions). Inspect bearings and re­
lubricate or replace as required. Follow lubrication
instructions on special field supplied motors.
Fan shaft bearings on 008, 012, 016, 024, 028
and 034 sizes are lubricated for the life of the
bearings. The 044, 054 and 064 sizes have alemite
grease fittings. Lubricate annually with a good
grade of grease with a lithium base and rust
inhibitor or a mixed base grease.
Add grease until air bubbles from under the
seal. Do not over-grease.
Return Air Filters — Inspect filters twice monthly
and replace as often as required depending on
operating conditions. The correct filter size is
shown in Table 1. If cleanable filters are used, flush
them with hot water or steam or soak in a mild
solution of soap (or detergent) and water. Rinse
and allow filters to dry before recoating and
reinstalling. Refer to filter manufacturer’s instmc-
tions as applicable. Do not operate unit without
return air filters in place.
Condensate Drains — Clean drain line and unit
drain pan at the start of each cooling season. Check
flow by pouring water into drain. Be sure trap is
filled to maintain an air seal.
Evaporator Coil — Remove dirt and debris from
evaporator coil as required. Clean with a stiff
bmsh, vacuum cleaner or compressed air. Use a fin
comb with teeth of correct spacing when straight­
ening mashed or bent coil fins (see Table 1).
Water-Cooled Condenser may require cleaning of
scale (water deposits). Condensers are best cleaned
with an inhibited hydrochloric acid solution such
as Oakite 32. Acid will stain hands and clothing
and attack concrete. Without inhibitor, it will
attack steel. Cover surroundings to guard against
splashing. Vapors from vent pipe are not harmful,
but take care to prevent liquid from being carried
over by the gases. Warm solution acts more readily,
but cold solution applied longer is just as effective.
GRAVITY FLOW METHOD (Fig. 27) - Do not
add solution faster than vent can exhaust generated
gases. When condenser is full, allow solution to
remain overnight, then drain condenser and flush
with clean water. Follow acid manufacturer’s
instructions.
FORCED CIRCULATION METHOD (Fig. 28 ) -
Fully open vent pipe when filling condenser. Vent
may be closed when condenser is full and pump is
operating. Regulate flow to condenser with supply
line valve. If pump is nonoverloading type, valve
may be fully closed when pump is running.
For average scale deposit, allow solution to
remain in condenser overnight. For heavy deposits,
allow 24 hours. Drain condenser and flush with clean
water. Follow acid manufacturer’s instructions.
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