27
To correct phase order:
1. Turn off power to the uni t, tag disconnect.
2. Reverse any two of the unit power leads.
3. Reapply power to the compressor, verify correct
pressures.
To verify the compress or is rotating in the prop er
direction:
1. Connect service gages to the suction and liquid
pressure fittings.
2. Energize the compressor.
3. The suction pressure should drop and the liquid
pressure should rise, as is normal on any start--up.
Compressor Ove rload —
This overload interrupts power to the compressor when
either the current or internal motor winding temperature
becomes excessive, and automatically resets when the
internal temperature drops to a safe level. This overload
may require up to 60 minute s (or longer) to reset. If the
internal overload is suspected of being open, disconnect
the electrical power to the unit and check the circuit
through the overload with an ohmmeter or conti nuity
tester.
Advanced Scroll Temperature Protection (ASTP) —
A label located above the terminal box identifies Copeland
Scroll compressor models that contain this technology. See
Fig. 21. Advanced Scroll Temperature Protection (ASTP) is
a f or m of internal dis charge temp eratu re p ro tectio n, that
unloads the scroll compressor when the internal temperature
reaches appro x imately 149_C (300_F ). At this temperature,
an internal bi--metal disk valve opens and causes the scr oll
elements to separate, which stops compression. Suction and
discharge pressures balance while the motor continues to
run. The longer the compressor runs unloaded, the longer it
must cool before the bi--metal disk resets. See Fig. 22.
To manua lly 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.
C10080
Fig. 21 -- Advanced Scroll Temperature Protection Label
0
10
20
30
40
50
60
70
80
90
100
110
120
0 10203040 6070809050
Compressor Unloaded Run Time (Minutes)*
*Times are approximate.
NOTE: Various factors, including high humidity, high ambient
temperature, and the presence of a sound blanket will
increase cool-down times.
Recommended Cooling Time*
(Minutes)
C10081
Fig. 22 -- Recommended Minimum Cool-Down Time
After Compressor is Stopped
Start Unit
Set the space thermostat to a set point above space
temperature so that there is no demand for cooling. Cl ose
the 38AU 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
dama ge.
Never charge liquid into the low-pressure side of
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 Motormaster function.
CAUTION
!
Adjust Refrigerant Charge —
Refer to Cooling Charging Charts, Fig. 24 through Fig. 29.
For applications with line lengths greater than 125 ft (38 m),
contact Carrier representative. Make sure that all condenser
fans are operating, and on units with the HGBP (hot pass
bypass) option make sure that the HGBP solenoid valve is
deactivated (see procedur e below) , befor e adjus tin g char g e
to the charging charts. Vary refrigerant until the conditions of
the chart are met. Note that the char gin g charts are dif f er ent
from the type normally used. The charts are based on
charging the units to the correct subcooling for the various
operating conditions. Accurate pressure gage and
temperature sensing device are required. Connect the
pressure gage to the service port on the liquid line service
valve. Mount the temperature sensing device on the liquid
line clos e to the liquid line ser vice valve, and insu late 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
stab ilized. Plot the liquid pres s ur e and temperature on chart
38AU
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