Carrier 50BA - Manual (Page 20)

Lubrication — Observe fan compartment
CAUTION note.
The fan motor bearings are factory lubricated and
will need no lubrication for the first 5 years of opera­
tion (3 years at continuous service or excessively
dirty conditions).
Inspect bearings and relubricate or replace as
required. If heating coil is installed, oil bearings
every 6 months. Follow lubrication instructions on
special field-supplied motors.
Fan shaft bearings on 50BA,BB004 thru 034 units
are lubricated for the life of the bearings. The 50BA,
BB044, 054 and 064 units have alemite grease
fittings. Lubricate annually with a good grade of
mixed base grease or lithium base grease with rust
inhibitor. Add grease until air bubbles form under
the seal. Do not overgrease.
Return-Air Filters — Inspect filters twice monthly
and replace as often as required by operating condi­
tions. Filter size and type are listed in Table 1.
If cleanable filters are used, flush them with hot
water or steam or soak them in a mild water solu­
tion of soap or detergent. Refer to filter manu­
facturer’s instructions as applicable.
Do not operate the unit at any time without
return-air filters in place. For access to filters, refer
to the Service sections entitled. Access Panel
Removal, and Return-Air Grille Removal as
required.
Condensate Drains — Clean the 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 as shown in Fig. 26 to maintain an air seal.
Evaporator Coil — Observe fan compartment
CAUTION note at the beginning of the SERVICE
section.
Remove dirt and debris from evaporator coil as
required by condition. Clean coil with a stiff brush,
vacuum cleaner or compressed air. Use a fin comb of
the correct fins/in. spacing (Table 1) when straight­
ening mashed or bent coil fins.
Water-Cooled Condenser (50BA units) may
require cleaning of water-deposited scale.
Condensers are best cleaned with an inhibited
hydrochloric acid solution such as Oakite 32. The
acid can stain hands and clothing, attack concrete
and, without inhibitor, can 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 is just as effective if applied for a longer
period.
GRAVITY FLOW METHOD (Fig. 31) -- Do not
add solution faster than vent can exhaust the
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. 32) —
Fully open vent pipe when filling condenser. The
vent may be closed when condenser is full and pump
is operating.
Regulate flow to condenser with a supply line
valve. If pump is a nonoverloading type, the valve
may be fully closed while pump is running.
For average scale deposit, allow solution to re­
main in condenser overnight. For heavy scale
deposit, allow 24 hours. Drain condenser and flush
with clean water. Follow acid manufacturer’s
instructions.
Fig. 32 — Forced Circulation Method
Air-Cooled Condenser (50BB units) — Inspect
and clean periodically, depending upon operating
conditions. Follow the service instructions provided
for the make of condenser used.
Charging the System — On unit Sizes 008 thru
064, sight glasses are provided at inlet of each expan­
sion valve. These glasses are used in the field
charging procedure.
i
20