Carrier 50EJ, 50EW Belt Tension Adjustment Ð To adjust belt tension, Condenser-Fan Adjustment

Belt Tension Adjustment Ð To adjust belt tension:

1.Remove power to unit.

2.Remove motor mount nuts and bolts.

3.Loosen fan motor nuts. See Fig. 39.

4.Turn motor jacking bolts to move motor mounting plate left or right for proper belt tension. A slight bow should be present in the belt on the slack side of the drive while running under full load.

5.Tighten nuts.

6.Adjust bolts and nut on mounting plate to secure motor in ®xed position. Recheck belt tension after 24 hours of operation. Adjust as necessary.

Condenser-Fan Adjustment

1.Shut off unit power supply.

2.Remove fan guard.

3.Loosen fan hub setscrews.

4.Adjust fan height on shaft using a straightedge placed across venturi and measure per Fig. 40.

5.Tighten setscrews and replace fan guard.

6.Turn on unit power.

Evaporator-Fan Motor Replacement

1.Shut off unit power supply.

2.Remove upper outside panel and open hinged door to gain access to motor.

Fig. 39 Ð Belt Tension Adjustment

Fig. 40 Ð Condenser-Fan Adjustment

3.Fully retract motor plate adjusting bolts.

4.Loosen the 2 rear (nearest the evaporator coil) motor plate nuts.

5.Remove the 2 front motor plate nuts and carriage bolts.

6.Slide motor plate to the rear (toward the coil) and re- move fan belt(s).

7.Slide motor plate to the front and hand tighten one of the rear motor plate nuts (tight enough to prevent the motor plate from sliding back but loose enough to allow the plate to pivot upward).

8.Pivot the front of the motor plate upward enough to al- low access to the motor mounting hex bolts and secure in place by inserting a prop.

9.Remove the nuts from the motor mounting hex bolts and remove motor.

10.Reverse above steps to install new motor.

Power Failure Ð Dampers have a spring return. In event of power failure, dampers will return to fully closed position until power is restored.

Refrigerant Charge Ð Amount of refrigerant charge is listed on unit nameplate and in Table 1. Refer to Carrier GTAC II; Module 5; Charging, Recovery, Recycling, and Rec- lamation section for charging methods and procedures.

Unit panels must be in place when unit is operating dur- ing charging procedure.

NO CHARGE Ð Use standard evacuating techniques. After evacuating system, weigh in the speci®ed amount of refrig- erant (refer to Table 1).

LOW CHARGE COOLING Ð Using appropriate cooling charging chart (see Fig. 41 and 42), add or remove refrig- erant until conditions of the appropriate chart are met. Note that charging chart is different from those normally used. An accurate pressure gage and temperature sensing device are required. Measure liquid line pressure at the liquid line serv- ice valve using pressure gage. Connect temperature sensing device to liquid line near the liquid line service valve and insulate it so that outdoor ambient temperature does not af- fect reading. Indoor-air cfm must be within normal operat- ing range of unit. Take outdoor ambient temperature and read the suction pressure gage. Refer to appropriate chart to de- termine correct suction temperature. If intersection point on chart is above the curve, add refrigerant. If intersection point on chart is below curve, carefully recover some of the charge. Recheck suction pressure as charge is adjusted.

Filter Drier Ð Replace whenever refrigerant system is exposed to atmosphere.

Thermostatic Expansion Valve (TXV) Ð Each cir- cuit has one. It is nonadjustable and is factory set to main- tain 10 to 13° F superheat leaving the evaporator coil. Con- trols ¯ow of liquid refrigerant to the evaporator coils.

Protective Devices

COMPRESSOR PROTECTION

Overcurrent Ð Each compressor has one manual reset, cali- brated trip, magnetic circuit breaker. Do not bypass connec- tions or increase the size of the circuit breaker to correct trouble. Determine the cause and correct it before resetting the breaker.

Overtemperature Ð Each 06D type compressor (024-038 units only) has an internal protector to protect it against exces- sively high discharge gas temperatures.

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