Condenser-Fan Adjustment (Fig. 43) — Shut off unit power supply. Remove condenser-fan assembly (grille, motor, motor cover, and fan) and loosen fan hub setscrews. Adjust fan height as shown in Fig. 43. Tighten setscrews and replace condenser-fan assembly.
UNIT 48HJ | FAN HEIGHT — “A” (in.) |
004-006 and 007 (208/230 V) | 2.75 |
007 (460 and 575 V) | 3.50 |
Fig. 43 — Condenser-Fan Adjustment
Economizer Adjustment — Refer to Optional Econo- mizer sections on pages 12 and 15.
Evaporator Fan Belt Inspection — Check condition of evaporator belt or tension during heating and cooling inspec- tions or as conditions require. Replace belt or adjust as necessary.
High-Pressure Switch — The high-pressure switch contains a Schrader core depressor, and is located on the com- pressor hot gas line. This switch opens at 428 psig and closes at 320 psig. No adjustments are necessary.
Loss-of-Charge Switch — The loss-of-charge switch contains a Schrader core depressor, and is located on the com- pressor liquid line. This switch opens at 7 psig and closes at 22 psig. No adjustments are necessary.
Freeze-Stat — The freeze-stat is a bimetal temperature- sensing switch that is located on the “hair-pin” end of the evap- orator coil. The switch protects the evaporator coil from freeze- up due to lack of airflow. The switch opens at 30 F and closes at 45 F. No adjustments are necessary.
Refrigerant Charge — Amount of refrigerant charge is listed on unit nameplate (also refer to Table 1). Refer to Carrier GTAC2-5 Charging, Recovery, Recycling, and Reclamation training manual and the following procedures.
Unit panels must be in place when unit is operating during charging procedure. Unit must operate a minimum of 10 min- utes before checking or adjusting referigerant charge.
An accurate superheat, thermocouple- or thermistor-type thermometer, and a gage manifold are required when using the superheat charging method for evaluating the unit charge. Do not use mercury or small dial-type thermometers because they are not adequate for this type of measurement.
NO CHARGE — Use standard evacuating techniques. After evacuating system, weigh in the specified amount of refriger- ant. (Refer to Table 1.)
LOW CHARGE COOLING — Using Cooling Charging Charts, Fig. 44-47, vary refrigerant until the conditions of the charts are met. Note the charging charts are different from type normally used. Charts are based on charging the units to the correct superheat for the various operating conditions. Accu- rate 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 ambient temperature does not af- fect the reading. Indoor-air cfm must be within the normal op- erating range of the unit.
MOISTUREMISER SYSTEM CHARGING — The system charge for units with the MoistureMiser option is greater than that of the standard unit alone. The charge for units with this option is indicated on the unit nameplate drawing. Also refer to Fig. 48-51. To charge systems using the MoistureMiser
Dehumidification package, fully evacuate, recover, and re- charge the system to the nameplate specified charge level.
To check or adjust refrigerant charge on systems using the MoistureMiser Dehumidification package, charge per Fig. 48-
51.The subcooler MUST be energized to use the charging charts. The charts reference a liquid pressure (psig) and temperature at a point between the condenser coil and the subcooler coil. A tap is provided on the unit to measure liquid pressure entering the subcooler.
IMPORTANT: The subcooler charging charts (Fig. 48-
51)are to be used ONLY with units having the optional MoistureMiser subcooling option. DO NOT use standard charge (Fig. 44-47) for units with MoistureMiser option, and DO NOT use Fig. 48-51 for standard units.
Fig. 44 — Cooling Charging Chart,
Standard 48HJ004
Fig. 45 — Cooling Charging Chart,
Standard 48HJ005
