Carrier 17/19EX - Manual (Page 81)

Default Screen Freeze
Whenever an alarm occurs, the LID default screen will freeze displaying the condition of the
machine at the time of alarm. Knowledge of the operating state of the chiller at the time an
alarm occurs is useful when troubleshooting. Current machine information can be viewed on the
Status tables. Once all existing alarms are cleared (by pressing the RESET softkey), the default
LID will return to normal operation.
Motor Cooling Control (Hermetic Motors Only)
Motor temperature is reduced by refrigerant entering the motor shell and evaporating. The
refrigerant is regulated by the motor cooling relay. This relay will energize when the compressor
is running and motor temperature is above 125 F (51.7 C). The relay will close when motor
temperature is below 100 F (37.8 C). Note that there is always a minimum flow of refrigerant
when the compressor is operating for motor cooling; the relay only controls additional
refrigerant to the motor.
Note: An additional motor cooling relay is not required for Hermetic FA style compressors.
Auxiliary Oil Pump Control (Open Drive Machines Only)
The auxiliary oil pump (optional) is controlled by the PIC. During start-up, if the main oil pump
cannot raise pressure to 18 psid (124 kPa), the auxiliary oil pump will be energized. During
compressor operation, the auxiliary oil pump will be energized if the oil pressure falls below the