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48
FILTERS — Clean or replace at the start of each heating and
cooling season, or more often if operating conditions require it.
Replacement filters must be the same dimensions as original
filters.
OUTDOOR-AIR INLET SCREEN — Clean the screen with
steam or hot water and a mild detergent. Do not use disposable
filters in place of screens.
Lubrication
COMPRESSORS — Each compressor is charged with correct
amount of oil at the factory.
FAN MOTOR BEARINGS — Fan motor bearings are per-
manently lubricated. No further lubrication of outdoor or
indoor-fan motors is required.
Outdoor Fan Adjustment (Fig. 46)
1. Shut off the unit power supply and tag disconnect.
2. Remove the outdoor-fan assembly (grille, motor, motor
cover, and fan) and loosen the fan hub setscrews.
3. Adjust the fan height as shown in Fig. 46.
4. Tighten the setscrews and replace the outdoor-fan assembly.
Blower Belt Adjustment — Inspect the blower belt
for wear, proper belt tension, and pulley alignment as condi-
tions require or at the beginning of each heating and air condi-
tioning season.
Refer to Step 7 — Adjust Indoor-Fan Speed on page 25 for
adjustment and alignment procedures.
High-Pressure Switch — Located on the compressor
hot gas line is a high-pressure switch, which contains a
Schrader core depressor. This switch opens at 428 psig and
closes at 320 psig. No adjustment is necessary. Refer to
Table 1.
Loss-of-Charge Switch — Located on the outdoor liq-
uid line is a low-pressure switch which functions as a loss-of-
charge switch. This switch contains a Schrader core depressor.
This switch opens at 7 psig and closes at 22 psig. No adjust-
ment is necessary. Refer to Table 1.
Freezestat — Located on the “hair pin” end of the indoor
coil is a bimetal temperature sensing switch. This switch pro-
tects the evaporator coil from freeze-up due to lack of airflow.
The switch opens at 30 F and closes at 45 F. No adjustment is
necessary. Refer to Table 1.
Refrigerant Charge — The amount of refrigerant charge
is listed on the unit nameplate (also refer to Table 1). Refer to
Carrier Refrigerant Service Techniques Manual, Refrigerants
section.
Unit panels must be in place when the unit is operating
during charging procedure.
NO CHARGE — Use standard evacuating techniques. After
evacuating the system, weigh in the specified amount of refrig-
erant (refer to Table 1).
LOW CHARGE COOLING — Use the Cooling Charging
Charts, Fig. 47-49. Vary the refrigerant until the conditions of
the appropriate chart are met. Note that the charging charts are
different from the type normally used. Charts are based on
charging the units to the correct superheat for the various oper-
ating conditions. An accurate pressure gage and temperature
sensing device are required. Connect the pressure gage to the
service port on the suction line. Mount the temperature sensing
device on the suction line and insulate it so that outdoor ambi-
ent temperature does not affect the reading. Indoor-air cfm
must be within the normal operating range of the unit.
TO USE COOLING CHARGING CHARTS — Take the out-
door ambient temperature and read the suction pressure gage.
Refer to the appropriate chart to determine what the suction
temperature should be. If the suction temperature is high, add
refrigerant. If the suction temperature is low, carefully recover
some of the charge. Recheck the suction pressure as charge is
adjusted.
EXAMPLE: (Fig. 47)
Outdoor Temperature . . . . . . . . . . . ..................85F
SuctionPressure ...............................70psig
Suction Temperature should be . . . ..................49F
(Suction Temperature may vary ±5° F.)
HEATING CHARGE — Do not attempt to adjust refrigerant
charge while the unit is operating in the heating mode. If the
charge amount is believed to be incorrect, recover refrigerant
and weigh in the amount listed on the unit rating plate.
Replacement Parts — A complete list of replacement
parts can be obtained from any Carrier distributor.
Fig. 46 — Outdoor Fan Adjustment
UNIT
VOLTAGE
“A”
in.
208/230 V 2.75
460 V and 575 V 3.50
Fig. 47 — Cooling Charging Chart, 50TFQ008