Carrier 19XL User Manual
Page 121
confirm stop command)
•
recycle condition is present (see
section)
•
time schedule has gone into UNOCCUPIED mode (machine protective limit has been
reached and machine is in alarm)
•
the start/stop status is overridden to stop from the CCN network or the LID
When a stop signal occurs, the shutdown sequence first stops the compressor by
deactivating the start relay. A status message of ‘‘SHUTDOWN IN PROGRESS,
COMPRESSOR DEENERGIZED’’ is displayed. The guide vanes are then brought to the closed
position. The oil pump relay and the chilled water/brine pump relay are shut down 60 seconds
after the compressor stops. The condenser water pump will be shut down when the
CONDENSER REFRIGERANT TEMP
is less than the
CONDENSER PRESSURE OVERRIDE
minus 5 psi (34 kPa) or is less than or equal to the
ENTERING CONDENSER WATER TEMP
plus 3° F (2° C). The stop-to-start timer will now begin to count down. If the start-to-start timer is
still greater than the value of the start-to-stop timer, then this time is now displayed on the LID.
Certain conditions during shutdown will change this sequence:
•
if the
COMPRESSOR MOTOR LOAD
is greater than 10% after shutdown, or the
starter contacts remain energized, the oil pump and chilled water pump remain ener-
gized and the alarm is displayed
•
if the
ENTERING CONDENSER WATER
temperature is greater than 115 F (46 C) at
shutdown, the condenser pump will be deenergized after the 1CR compressor start
relay