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Fig. 14 — Advanced Scroll Temperature Protection
120
110
100
90
80
70
60
50
40
30
20
10
0
0
10
20
30
Compressor Unloaded Run Time (Minutes)*
NOTES:
1 . Various factors, including high humidity, high ambient temperature,
and the presence of a sound blanket will increase cool-down times.
*Times are approximate.
Fig. 15 — Recommended Minimum Cool-Down Time
After Compressor is Stopped
To manually reset ASTP, the compressor should be stopped and
allowed to cool. If the compressor is not stopped, the motor will
run until the motor protector trips, which occurs up to 90 minutes
later. Advanced Scroll Temperature Protection will reset
automatically before the motor protector resets, which may take
up to 2 hours.
Label
40
50
60
70
80
90
START UNIT
Set the space thermostat to a set point above space temperature so
that there is no demand for cooling. Close the 38AUQ disconnect
switch. Only the crankcase heater will be energized.
Reset the space thermostat below ambient so that a call for cooling
is ensured.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment damage.
Never charger liquid into the low-pressure side of the system.
Do not overcharge. During charging or removal of refrigerant,
be sure indoor-fan system is operating. Ensure both outdoor
fan motors are running; bypass any low ambient sensor
function.
ADJUST REFRIGERANT CHARGE
The unit must be charged in Cooling mode only. Refer to Cooling
Charging Charts, Fig. 16 and 17. For applications with line lengths
greater than 100 ft, contact Carrier representative. Vary refrigerant
until the conditions of the chart are met. The charts are based on
charging the units to the correct subcooling for the various operat-
ing conditions. Accurate pressure gauge and temperature sensing
device are required. Connect the pressure gauge to the service port
on the liquid line service valve. Mount the temperature sensing de-
vice on the liquid line close to the liquid line service valve, and in-
sulate it so that outdoor ambient temperature does not affect the
reading. Indoor airflow must be within the unit's normal operating
range. Operate the unit for a minimum of 15 minutes. Ensure that
pressure and temperature readings have stabilized. Plot the liquid
pressure and temperature on chart and add or reduce the charge to
meet the curve. Adjust the charge to conform with the charging
chart, using the liquid pressure and temperature to read the chart.
FINAL CHECKS
Ensure that all safety controls are operating, control panel covers
are on, and the service panels are in place.
18
CAUTION
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