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A. No Charge
Use standard evacuating techniques. After evacuating sys-
tem to 500 microns, weigh in the specified amount of refrig-
erant. (Refer to Table 1 and unit information plate.)
B. Low Charge Cooling
Using Cooling Charging Charts, Fig. 48-51, 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 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.
C. Perfect Humidity™ System Charging
The system charge for units with the Perfect Humidity 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. 52-55. To charge systems using the
Perfect Humidity Dehumidification system, fully evacuate,
recover, and recharge the system to the unit information plate
specified charge level.
To check or adjust refrigerant charge on systems using the Per-
fect Humidity Dehumidification system, charge per Fig. 52-55.
NOTE: When using the charging charts, it is important that
only the subcooling/reheat dehumidification coil liquid line
solenoid valve be energized. The subcooling/reheat dehumid-
ification coil liquid line solenoid valve MUST be energized to
use the charging charts and the outdoor motor speed control-
ler jumpered to run the fan at full speed.
The charts reference a liquid pressure (psig) and tempera-
ture at a point between the condenser coil and the
subcooling/reheat dehumidification coil. A tap is provided on
the unit to measure liquid pressure entering the subcooling/
reheat dehumidification coil.
IMPORTANT: The subcooling mode charging charts
(Fig. 52-55) are to be used ONLY with units having the
optional Perfect Humidity subcooling option. DO NOT use
standard charge (Fig. 48-51) for units with Perfect Humidity
system, and DO NOT use Fig. 52-55 for standard units.
D. To Use Cooling Charging Chart, Standard Unit
Take the outdoor ambient temperature and read the suction
pressure gage. Refer to charts to determine what suction tem-
perature should be. If suction temperature is high, add refrig-
erant. If suction temperature is low, carefully recover some of
the charge. Recheck the suction pressure as charge is adjusted.
Example (Fig. 50):
Outdoor Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 F
Suction Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70 psig
Suction Temperature should be . . . . . . . . . . . . . . . . . . . .48 F
(Suction temperature may very ± 5 F.)
If charging device is used, temperature and pressure read-
ings must be accomplished using the charging charts.
Fig. 44 — Cleaning Condenser Coil
Fig. 45 — Propping Up Top Panel
Fig. 46 — Separating Coil Sections
Fig. 47 — Condenser-Fan Adjustment
UNIT 581B FAN HEIGHT — “A” (in.)
036-060 and 072 (208/230 V) 2.75
072 (460 and 575 V) 3.50