Faulted Chiller Operation; Load Balancing; Auto. Restart After Power Failure; Attach To Network Device Control - Carrier AquaEdge 23XRV Start-Up, Operation And Maintenance Instructions Manual

screen) plus on half of the CHILLED LIQUID DEAD-
BAND temperature (see the SETUP1 screen).
3. The configured LAG STOP TIMER entry has elapsed.
The LAG STOP TIMER starts when the lead chiller
CHILLED LIQUID TEMP is less than the chilled liquid
CONTROL POINT plus
DEADBAND and the lead chiller compressor motor load
(PERCENT MOTOR KILOWATTS or AVERAGE LINE
CURRENT on the MAINSTAT screen) is less than the
lead chiller percent capacity.
NOTE: The use of AVERAGE LINE CURRENT or PERCENT
MOTOR KILOWATTS in the Lag chiller shutdown decision
is based on the DEMAND LIMIT SOURCE configuration in
the RAMP_DEM screen. If DEMAND LIMIT SOURCE = 0
then AVERAGE LINE CURRENT will be used. If DEMAND
LIMIT SOURCE = 1 then PERCENT MOTOR KILOWATTS
will be used.
FAULTED CHILLER OPERATION — If the lead chiller
shuts down because of an alarm (*) condition, it stops commu-
nicating to the lag and standby chillers. After 30 seconds, the
lag chiller becomes the acting lead chiller and starts and stops
the standby chiller, if necessary.
If the lag chiller goes into alarm when the lead chiller is also
in alarm, the standby chiller reverts, after 60 seconds, to a
stand-alone CCN mode of operation.
If the lead chiller is in an alarm (*) condition (as shown on
the ICVC panel), press the
RESET
The lead chiller is placed in CCN mode. The lead chiller
communicates and monitors the RUN STATUS of the lag and
standby chillers. If both the lag and standby chillers are
running, the lead chiller does not attempt to start and does not
assume the role of lead chiller until either the lag or standby
chiller shuts down. If only one chiller is running, the lead
chiller waits for a start request from the operating chiller. When
the configured lead chiller starts, it resumes its role as lead
chiller.
If the lag chiller is the only chiller running and the lead
chiller is ready to resume its role as a lead chiller then the lag
chiller will perform a RECOVERY START REQUEST (LL_-
MAINT screen). The lead chiller will start up when the follow-
ing conditions are met.
1. Lag chiller ramp loading must be complete.
2. Lag CHILLED LIQUID TEMP (MAINSTAT screen)
is greater than CONTROL POINT plus
CHILLED LIQUID DEADBAND temperature.
3. Lag chiller ACTIVE DEMAND LIMIT value must be
greater than 95% of full load amps.
4. Lag chiller temperature pulldown rate (TEMP PULL-
DOWN DEG/MIN) of the chilled liquid temperature is
less than 0.5 F (0.27 C) per minute for a cumulative
time duration greater than the PULLDOWN TIMER
setting in the lag chiller's LEADLAG screen.
5. The standby chiller is not running as a lag chiller.
6. The configured LAG START TIMER has elapsed. The
LAG START TIMER is started when ramp loading is
completed.
LOAD BALANCING — When the LOAD BALANCE OP-
TION (see LEADLAG screen) is enabled, the lead chiller sets
the ACTIVE DEMAND LIMIT in the lag chiller to the lead
chiller's AVERAGE LINE CURRENT or PERCENT MOTOR
KILOWATTS value in the POWER screen. This value has
limits of 40% to 100%. When the lag chiller ACTIVE
DEMAND LIMIT is set, the CONTROL POINT is assigned a
value of 3º F (1.67º C) less than the lead chiller's CONTROL
POINT value to better match the lead chiller's load level. If the
1 / of the CHILLED LIQUID
2
softkey to clear the alarm.
/ the
1
2
LOAD BALANCE OPTION is disabled, the ACTIVE
DEMAND LIMIT and the CONTROL POINT are forced to the
same value as the lead chiller.
AUTO. RESTART AFTER POWER FAILURE —
an Auto restart condition occurs, each chiller may have a delay
added to the start-up sequence, depending on its lead/lag
configuration. The lead chiller does not have a delay. The lag
chiller has a 45-second delay. The standby chiller has a
90-second delay. The delay time is added after the chiller liquid
flow is verified. The delay must elapse before the oil pump is
turned on. The Auto restart delay sequence occurs whether the
chiller is in CCN or LOCAL mode and is intended to stagger
the compressor motor starts. Preventing the motors from start-
ing simultaneously helps reduce the inrush demands on the
building power system.
Attach to Network Device Control —
menu includes the ATTACH TO NETWORK DEVICE
screen. From this screen the operator can:
• attach the ICVC to any CCN device, if the chiller has
been connected to a CCN network. This may include
other PIC III-controlled chillers.
• upgrade software
Figure 35 shows the ATTACH TO NETWORK DEVICE
screen. The LOCAL parameter is always the ICVC module
address of the chiller on which it is mounted. Whenever the
controller identification of the ICVC changes, the change is re-
flected automatically in the BUS and ADDRESS columns for
the local device. See Fig. 28. Default address for local device is
BUS 0 ADDRESS 1.
When the ATTACH TO NETWORK DEVICE screen is
accessed, information can not be read from the ICVC on any
device until one of the devices listed on that screen is attached.
The ICVC erases information about the module to which it was
attached to make room for information on the new device.
Therefore, a CCN module must be attached when this screen is
entered.
To attach any CCN device, highlight it using the
softkey and press the
LOADING TABLES, PLEASE WAIT" displays. The ICVC
then uploads the highlighted device or module. If the module
address cannot be found, the message "COMMUNICATION
FAILURE" appears. The ICVC then reverts back to the
ATTACH TO DEVICE screen. Try another device or check the
address of the device that would not attach. The upload process
time for each CCN module is different. In general, the upload-
ing process takes 1 to 2 minutes. Before leaving the ATTACH
TO NETWORK DEVICE screen, select the local device. Oth-
erwise, the ICVC will be unable to display information on the
local chiller.
Fig. 35 — Example of Attach to Network
Device Screen
58
The Service
softkey. The message "UP-
ATTACH
When
SELECT
a23-1611