Carrier 50TFQ008-012 specifications Lubrication

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.

UNIT	“A”
VOLTAGE	in.
208/230 V	2.75
460 V and 575 V	3.50

Fig. 46 — Outdoor Fan Adjustment

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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 F Suction Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 psig Suction Temperature should be . . . . . . . . . . . . . . . . . . . . . 49 F (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. 47 — Cooling Charging Chart, 50TFQ008

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