Page 11
1
2
3
4
SUCTION
SUCTION
ORBITING SCROLL
STATIONARY SCROLL
SUCTION
SUCTION
DISCHARGE
SUCTION
INTERMEDIATE PRESSURE
GAS
CRECENT SHAPED
GAS POCKET
HIGH PRESURE GAS
FLANKS SEALED
BY CENTRIFIGUAL
FORCE
MOVEMENT OF ORBIT
FIGURE 10
Three-Phase Compressor Rotation
Three-phase scroll compressors must be phased sequen-
tially to ensure correct compressor rotation and operation.
At compressor start-up, a rise in discharge and drop in suc-
tion pressures indicates proper compressor phasing and
operation. If discharge and suction pressures do not per-
form normally, follow the steps below to correctly phase the
unit.
1 − Disconnect power to the unit.
2 − Reverse any two field power leads to the unit.
3 − Reapply power to the unit.
Discharge and suction pressures should operate within
their normal start-up ranges.
NOTE − Compressor noise level may be significantly higher
when phasing is incorrect and the unit will not provide cool-
ing when compressor is operating backwards. Continued
backward operation will cause the compressor to cycle on
internal protector.
C − Outdoor Fan Motor
All units use single−phase PSC fan motors which require a run
capacitor. In all units, the condenser fan is controlled by
the compressor contactor.
ELECTRICAL DATA tables in this manual show specifi-
cations for condenser fans used in HPXA12s.
Access to the condenser fan motor on all units is gained
by removing the seven screws securing the fan assem-
bly. See figure 11. The condenser fan motor is removed
from the fan guard by removing the four nuts found on the
top panel. If condenser fan motor must be replaced,
align fan hub flush with motor shaft. Drip loops should be
used in wiring when servicing motor.
FAN
CONDENSER FAN MOTOR
AND COMPRESSOR ACCESS
Remove (7) screws
REMOVE (7) SCREWS
SECURING FAN GUARD.
REMOVE FAN GUARD/FAN
ASSEMBLY.
FAN GUARD
WIRING
FIGURE 11
Remove (4) nuts
ALIGN FAN HUB
FLUSH WITH
MOTOR SHAFT
D − Reversing Valve L1 and Solenoid
A refrigerant reversing valve with electromechanical so-
lenoid is used to reverse refrigerant flow during unit op-
eration. The reversing valve requires no maintenance. It
is not repairable. If the reversing valve has failed, it must
be replaced.
If replacement is necessary, access reversing valve by re-
moving the outdoor fan motor. Refer to figure 11.
E − Crankcase Heater HR1
An insertion type crankcase heater is factory installed on
HPXA12−048 and −060 three phase units only. The heat-
er is temperature actuatedated and operates only when
required.
