Carrier 48HE003---006 48HE,HJ, Loss-of-ChargeSwitch, Freeze-Stat, RefrigerantCharge, No charge

48HE,HJ

Step 7 —Loss-of-Charge Switch

The loss-of-charge switch contains a Schrader core depressor, and is located on the compressor liquid line. This switch opens at 7 psig and closes at 22 psig. No adjustments are necessary.

Step 8 —Freeze-Stat

The freeze-stat is a bimetal temperature-sensing switch that is located on the “hair-pin” end of the evaporator 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.

Step 9 —Refrigerant Charge

Amount of refrigerant charge is listed on unit nameplate (also refer to Table 1). Refer to HVAC Servicing Procedures literature available at your local distributor and the following procedures.

Unit panels must be in place when unit is operating during charging procedure. Unit must operate a minimum of 10 minutes before checking or adjusting refrigerant charge.

An accurate superheat, thermocouple-type or thermistor-type thermometer, and a gauge 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 to 500 microns, weigh in the specified amount of refrigerant. (Refer to Table 1 or 2 and unit information plate.)

Low charge cooling

Using Cooling Charging Charts, Fig. 60-63, 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. Accurate pressure gage and temperature sensing device are required. Connect the pressure gauge 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 affect the reading. Indoor-air cfm must be within the normal operating range of the unit.

HUMIDI-MIZER™SYSTEM CHARGING

The system charge for units with the Humidi-MiZer adaptive dehumidification system 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. 64-67. To charge systems using the Humidi-MiZer adaptive dehumidification system, fully evacuate, recover, and recharge the system to the nameplate specified charge level. To check or adjust refrigerant charge on systems using the Humidi-MiZer adaptive dehumidification system, charge per Fig. 64-67.

C06139

Fig. 60 ---Cooling Charging Chart,

Standard 48HJ004

C06140

Fig. 61 ---Cooling Charging Chart,

Standard 48HJ005

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