Carrier 48LJD - Manual (Page 23)

LOW CHARGE COOLING — Using Cooling Charging
Charts, Fig. 32-35, vary refrigerant until the conditions of
the appropriate chart are met. Note the charging charts are
different from type normally used. Charts are based on charg­
ing the units to the correct superheat for the various oper­
ating conditions. 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 ambient temperature does not affect the reading.
Indoor-air cfm must be within the normal operating range
of the unit.
TO USE COOLING CHARGING CHART - Take the out­
door ambient temperature and read the suction pressure gage.
Refer to chart to determine what suction temperature should
be. If suction temperature is high, add refrigerant. If suc­
tion temperature is low, carefully reclaim some of the charge.
Recheck the suction pressure as charge is adjusted.
Example; (Fig. 33)
Outdoor Temperature........................................................85F
Suction Pressure........................................................... 70 psig
Suction Temperature should be ....................................... 46 F
(Suction Temperature may vary 5 F.)
If Chargemaster® charging device is used, temperature
and pressure readings must be accomplished using the charg­
ing chart.
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SUCTION LINE TEMPERATURE CC)
Fig. 32 — Cooling Charging Chart, 48LJE/LJF004
30 40 SO BO
SUCTION LINE TEMPERATURE CF)
7 3 SO
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SUCTION LINE TEMPERATURE CC)
2'l h
Fig. 34 — Cooling Charging Chart, 48LJD/LJE/LJF006
Fig. 33 — Cooling Charging Chart, 48LJD/LJE/LJF005
Fig. 35 — Cooling Charging Chart, 48LJD/LJE/LJF007
23