Low Charge Cooling; Indoor Airflow And Airflow Adjustments - Payne PA3Z Installation Manual

4. Locate the measured suction line pressure in the top row of Table 8 and the measured outdoor ambient temperature in the left column of
the table. Based on the two values, determine the required suction line temperature.
5. If the measured suction line temperature is greater than the tabulated temperature, add charge in the system.
048 and 060 units:
1. Measure discharge line pressure by attaching a gauge to the service port.
2. Measure the liquid line temperature by attaching a temperature sensing device to it.
3. Insulate the temperature sensing device so that the outdoor ambient doesn't affect the reading.
4. Refer to the required subcooling in Tables 4 and 5 to find the required subcooling based on the model size and the outdoor ambient
temperature.
5. Interpolate if the outdoor temperature lies in between the table values. Extrapolate if the temperature lies beyond the table range.
6. Find the pressure value corresponding to the measured pressure on the compressor discharge line.
7. Read across from the pressure reading to obtain the Liquid line temperature for a required subcooling.
8. Add charge if the measured temperature is higher than the liquid line temperature value in the table.
9. Add charge using the service connection on the suction line of the compressor.
PROCEDURE 4—INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS
NOTE: For cooling operation, the recommended airflow is 350 to 450 cfm per each 12,000 Btuh of rated cooling capacity.
Table 7 shows dry coil air delivery for horizontal discharge units. Tables 9-11 show pressure drops.
NOTE: Be sure that all supply- and return-air grilles are open, free from obstructions, and adjusted properly.
WARNING: ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Disconnect electrical power to the unit and install lockout tag before changing blower speed.
Airflow can be changed by changing the 24 volts lead connections of the blower motor.
Unit PA3Z blower motors are factory wired for rated airflow operation.
SINGLE-PHASE
CONNECTIONS
3-PHASE
TO DISCONNECT
CONNECTIONS
PER NEC
TO DISCONNECT
PER NEC
Fig. 9—Line Power Connections
C
R
G
Y
W2
W3
Thermostat
and subbase
Fig. 10A—Control Connections (Sizes 024-042)
UNIT GROUND
GROUND
LEAD
L BLK
L
YEL
L
BLU
BROWN
RED
GREEN
YELLOW
WHITE
VIOLET
Unit Control
Power
A05213
—11—
C00012