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Failure to verify any of the requirements up to this point
will result in the PIC aborting the start and displaying the
applicable pre-start mode of failure on the LID default screen.
A pre-start failure does not advance the starts in 12 hours
counter. Any failure after the 1CR relay has energized re-
sults in a safety shutdown, energizes the alarm light, and dis-
plays the applicable shutdown status on the LID display.
Shutdown Sequence —
Shutdown of the machine can
occur if any of the following events happen:
• the STOP button is pressed for at least one second (the
alarm light will blink once to confirm stop command)
• recycle condition is present (see Chilled Water Recycle Mode
section)
• time schedule has gone into UNOCCUPIED mode
• remote contact opens
• 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, COMPRES-
SOR DEENERGIZED’’ is displayed. Compressor ontime
and service ontime stop. 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 CON-
DENSER 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 energized 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
• if the machine shuts down due to low refrigerant tempera-
ture, the chilled water pump will stay running until the
LEAVING CHILLED WATER is greater than CONTROL
POINT, plus 5° F (3° C)
Automatic Soft Stop Amps Threshold —
The SOFT
STOP AMPS THRESHOLD closes the guide vanes of the
compressor automatically when a non-recycle, non-alarm stop
signal occurs before the compressor motor is deenergized.
If the STOP button is pressed, the guide vanes close to a
preset amperage percent or until the guide vane is less than
2% open. The compressor will then shut off.
If the machine enters an alarm state or if the compressor
enters a RECYCLE mode, the compressor will be deener-
gized immediately.
To activate SOFT STOP AMPS THRESHOLD, view the
bottom of Service1 table. Set the SOFT STOP AMPS THRESH-
OLD value to the percentage amps at which the motor will
shut down. The default setting is 100% amps (no Soft Stop).
When the SOFT STOP AMPS THRESHOLD is being ap-
plied, a status message ‘‘SHUTDOWN IN PROGRESS, COM-
PRESSOR UNLOADING’’ is shown.
Chilled Water Recycle Mode —
The machine
may cycle off and wait until the load increases to restart
again when the compressor is running in a lightly loaded
condition. This cycling of the chiller is normal and is known
as recycle. A recycle shutdown is initiated when any of the
following conditions are true:
• when in LCW control, the difference between the LEAV-
ING CHILLED WATER temperature and ENTERING
CHILLED WATER temperature is less than the RECYCLE
SHUTDOWN DELTA T (found in the Service1 table) and
the LEAVING CHILLED WATER TEMP is below the CON-
TROL POINT, and the CONTROL POINT has not in-
creased in the last 5 minutes
• when ECW CONTROL OPTION is enabled, the difference
between the ENTERING CHILLED WATER temperature
and the LEAVING CHILLED WATER temperature is less
than the RECYCLE SHUTDOWN DELTA T (found in the
Service1 table) and the ENTERING CHILLED WATER TEM-
PERATURE is below the CONTROL POINT, and the CON-
TROL POINT has not increased in the last 5 minutes
• when the LEAVING CHILLED WATER temperature is within
3° F (2° C) of the BRINE REFRIG TRIPPOINT
When the machine is in RECYCLE mode, the chilled wa-
ter pump relay remains energized so that the chilled water
temperature can be monitored for increasing load. The re-
cycle control uses RECYCLE RESTART DELTA T to check
when the compressor should be restarted. This is an operator-
configured function which defaults to 5° F (3° C). This value
is viewed/modified on the Service1 table. The compressor
will restart when:
• in LCW CONTROL the LEAVING CHILLED WATER tem-
perature is greater than the CONTROL POINT plus the RE-
CYCLE RESTART DELTA T; or
• in ECW CONTROL, the ENTERING CHILLED WATER
temperature is greater than the CONTROL POINT plus the
RECYCLE RESTART DELTA T
Once these conditions are met, the compressor shall ini-
tiate a start-up, with a normal start-up sequence.
An alert condition may be generated if 5 or more RE-
CYCLE STARTUPs occur in less than 4 hours. This exces-
sive recycling can reduce machine life. Compressor recycling
due to extremely low loads should be reduced. To reduce
compressor recycling, use the time schedule to shut the ma-
chine down during low load operation or increase the ma-
chine load by running the fan systems. If the hot gas bypass
is installed, adjust the values to ensure that hot gas is ener-
gized during light load conditions. Increase the RECYCLE
RESTART DELTA T on the Service1 table to lengthen the
time between restarts.
The machine should not be operated below design mini-
mum load without a hot gas bypass installed on the
machine.
Safety Shutdown —
A safety shutdown is identical to
a manual shutdown with the exception that the LID will dis-
play the reason for the shutdown, the alarm light will blink
continuously, and the spare alarm contacts will be ener-
gized. A safety shutdown requires that the RESET softkey
be pressed in order to clear the alarm. If the alarm is still
present, the alarm light will continue to blink. Once the alarm
is cleared, the operator must press the
CCN
or
LOCAL softkeys to restart the machine.
Do not reset starter loads or any other starter safety for
30 seconds after the compressor has stopped. Voltage
output to the compressor start signal is maintained for
10 seconds to determine starter fault.
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Содержание 17
Страница 13: ...Fig 6 Open Drive 17 Series Lubrication Cycle 13 ...
Страница 15: ...Fig 7 17EX Controls and Sensor Locations 15 ...
Страница 16: ...Fig 7 17EX Controls and Sensor Locations cont 16 ...
Страница 17: ...Fig 7 17EX Controls and Sensor Locations cont 17 ...
Страница 19: ...Fig 8 19EX Controls and Sensor Locations cont 19 ...
Страница 23: ...Fig 16 17 19EX LID Menu Structure 23 ...
Страница 24: ...Fig 17 17 19EX Service Menu Structure 24 ...
Страница 50: ...Fig 28 17 19EX Leak Test Procedures 50 ...