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Table 34—Perfect Humidity Adaptive Dehumidification System Sequence of Operation and
THERMOSTAT INPUT
H
Y1
Y2
OAT. < Economizer Set Point
Off
—
—
On
On
On
On
On
Off
On
On
On
On
On
Off
On
Off
Off
NOTE: On a thermostat call for W1, all cooling and dehumidification will be off.
LEGEND
OAT --- Outdoor Air Temperature
Step 3 —Condenser- -Fan Adjustment
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. 50. Tighten
setscrews and replace condenser-fan assembly.
UNIT
024-060 and 072 (208/230 v)
072 (460 v)
Fig. 48 --- Condenser- -Fan Adjustment
Step 4 —EconoMi$er IV Adjustment
Refer to Optional EconoMi$er IV section.
Step 5 —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.
No Charge
Use standard evacuating techniques. After evacuating system to
500 microns, weigh in the specified amount of refrigerant. (Refer
to Table 1 and unit information plate.)
Low Charge Cooling
Using Cooling Charging Charts, Fig. 49- -52, 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 gauge 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. 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.
System Response — Single Compressor Unit (551C 024- -060, 551B 036- -072)
ECONOMIZER FUNCTION
Economizer
No
No
Yes
Yes
No
FAN HEIGHT (in.) - A
2.75
3.50
C06138
551B,C UNIT OPERATION
Comp. 1
Subcooling Mode
Normal Operation
Off
On
Off
On
On
On
On
On
Off
On
Fig. 49 --- Cooling Charging Chart,
Standard 551B 036
Perfect Humidity™ System Charging
The system charge for units with the Perfect Humidity 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. 53- -56. To charge
systems using the Perfect Humidity 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 Perfect Humidity adaptive
dehumidification system, charge per Fig. 53- -56.
52
Hot Gas Reheat Mode
Yes
No
Yes
No
Yes
No
No
Yes
No
Yes
C06139
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