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62
ICE BUILD INITIATION — The ice build time schedule
(OCCPC02S) is the means for activating the ice build option.
The ice build option is enabled if:
• a day of the week and a time period on the ice build time
schedule are enabled. The SCHEDULE screen shows an
X in the day field and ON/OFF times are designated for
the day(s),
•
and
the
ICE BUILD OPTION
is enabled.
The following events take place (unless overridden by a
higher authority CCN device).
•
CHILLER START/STO
P is forced to START.
• The
CONTROL POINT
is forced to the
ICE BUILD SET-
POINT
.
• Any force (Auto) is removed from the
ACTIVE
DEMAND LIMIT
.
NOTE: A parameter’s value can be forced, that is, the value
can be manually changed at the ICVC by an operator, changed
from another CCN device, or changed by other algorithms in
the PIC II control system.
NOTE: The Ice Build steps do not occur if the chiller is config-
ured and operating as a lag or standby chiller for lead/lag
operation and is actively being controlled by a lead chiller. The
lead chiller communicates the
ICE BUILD SET POINT
, the
desired
CHILLER START/STOP
state, and the
ACTIVE
DEMAND LIMIT
to the lag or standby chiller as required for
ice build, if configured to do so.
START-UP/RECYCLE OPERATION — If the chiller is not
running when ice build activates, the PIC II checks the follow-
ing conditions, based on the
ICE BUILD TERMINATION
value, to avoid starting the compressor unnecessarily:
• if
ICE BUILD TERMINATION
is set to the TEMP option
and the
ENTERING CHILLED WATER
temperature is
less than or equal to the
ICE BUILD SETPOINT
;
• if
ICE BUILD TERMINATION
is set to the CONTACTS
option and the remote contacts are open;
• if the
ICE BUILD TERMINATION
is set to the BOTH
(temperature and contacts) option and the
ENTERING
CHILLED WATER
temperature is less than or equal to
the
ICE BUILD SETPOINT
and the remote contacts are
open.
The
ICE BUILD RECYCLE
on the OPTIONS screen deter-
mines whether or not the chiller will go into an ice build RE-
CYCLE mode.
• If the
ICE BUILD RECYCLE
is set to
DSABLE
(disable),
the PIC II reverts to normal (non-ice build) temperature
control when the ice build function is terminated by satisfy-
ing one of the above conditions. Once ice build is termi-
nated in this manner, it will not be reinitiated until the next
ice build schedule period begins.
• If the
ICE BUILD RECYCLE
is set to
ENABLE
, the PIC II
goes into an
ICE BUILD RECYCLE
mode, and the chilled
water pump relay remains energized to keep the chilled
water flowing when the compressor shuts down. If the tem-
perature of the
LEAVING CHILLED WATER
later increases
above the
ICE BUILD SETPOINT
plus half the
RECYCLE
RESTART DELTA T
value, the compressor restarts, con-
trolling the chilled water/brine temperature to the
ICE
BUILD SETPOINT
.
TEMPERATURE CONTROL DURING ICE BUILD —
During ice build, the capacity control algorithm shall use the
CONTROL POINT
minus 5 F (–2.8 C) for control of the
LEAVING CHILLED WATER
temperature. The
ECW CON-
TROL OPTION
and any temperature reset option shall be ig-
nored, if enabled, during ice build. Also, the following control
options will be ignored during ice build operation:
•
ECW CONTROL OPTION
and any temperature reset
options (configured on TEMP_CTL screen).
•
20 mA DEMAND LIMIT OPT
(configured on
RAMP_DEM screen).
TERMINATION OF ICE BUILD — The ice build function
terminates under the following conditions:
1. Time Schedule — When the current time on the ice build
time schedule (OCCPC02S) is
not
set as an ice build time
period.
2. Entering Chilled Water Temperature — Ice build opera-
tion terminates, based on temperature, if the
ICE BUILD
TERMINATION
parameter is set to 0 (TEMP), the
EN-
TERING CHILLED WATER
temperature is less than the
ICE BUILD SETPOINT
, and the
ICE BUILD RECYCLE
is set to DSABLE. If the
ICE BUILD RECYCLE OP-
TION
is set to ENABLE, a recycle shutdown occurs and
recycle start-up depends on the
LEAVING CHILLED
WATER
temperature being greater than the water/brine
CONTROL POINT
plus the
RESTART DELTA T
temperature.
3. Remote Contacts/Ice Level Input — Ice build operation
terminates when the
ICE BUILD TERMINATION
param-
eter is set to 1 (CONTACTS) and the ice build contacts
are open and the
ICE BUILD RECYCLE
is set to
DSABLE (0). In this case, the contacts provide ice level
termination control. The contacts are used to stop the ice
build function when a time period on the ice build sched-
ule (OCCPC02S)
is
set for ice build operation. The re-
mote contacts can still be opened and closed to start and
stop the chiller when a specific time period on the ice
build schedule is
not
set for ice build.
4. Entering Chilled Water Temperature and ICE BUILD
Contacts — Compressor operation terminates when the
ICE BUILD TERMINATION
parameter is set to 2
(BOTH) and the conditions described above in items 2
and 3 for entering chilled water temperature and remote
contacts have occurred.
NOTE: It is not possible to override the
CHILLER START/
STOP, CONTROL POINT
, and
ACTIVE DEMAND LIMIT
variables from CCN devices (with a priority 4 or greater)
during the ice build period. However, a CCN device can over-
ride these settings during 2-chiller lead/lag operation.
RETURN TO NON-ICE BUILD OPERATIONS — The
ice build function forces the chiller to start, even if all other
schedules indicate that the chiller should stop. When the ice
build function terminates, the chiller returns to normal tem-
perature control and start/stop schedule operation. The
CHILLER START/STOP
and
CONTROL POINT
return to nor-
mal operation. If the
CHILLER START/STOP
or
CONTROL
POINT
has been forced (with a device of less than 4 priority)
before the ice build function started, when the ice build func-
tion ends, the previous forces (of less than 4 priority) are not
automatically restored.
Attach to Network Device Control —
The Service
menu includes the ATTACH TO NETWORK DEVICE
screen. From this screen, the operator can:
• enter the time schedule number (if changed) for
OCCPC03S, as defined in the NET_OPT screen
• attach the ICVC to any CCN device, if the chiller has
been connected to a CCN network. This may include
other PIC-controlled chillers.
• upgrade software
Figure 29 shows the ATTACH TO NETWORK DEVICE
screen. The
LOCAL
parameter is always the ICVC module ad-
dress of the chiller on which it is mounted. Whenever the con-
troller identification of the ICVC changes, the change is re-
flected automatically in the BUS and ADDRESS columns for
the local device. See Fig. 21. Default address for local device is
BUS 0 ADDRESS 1.
Summary of Contents for AquaEdge 19XR series
Page 69: ...69 Fig 33 19XR Leak Test Procedures a19 1625 ...
Page 154: ...154 Fig 64 Benshaw Inc Wye Delta Unit Mounted Starter Wiring Schematic Low Voltage a19 1873 ...
Page 161: ...161 Fig 69 Typical Low Voltage Variable Frequency Drive VFD Wiring Schematic 575 v ...
Page 162: ...162 Fig 69 Typical Low Voltage Variable Frequency Drive VFD Wiring Schematic 575 v cont ...
Page 186: ...186 APPENDIX B LEAD LAG WIRING 19XR Lead Lag Schematic Series Cooler Flow a19 1655 ...
Page 187: ...187 APPENDIX B LEAD LAG WIRING cont 19XR Lead Lag Schematic Parallel Cooler Flow a19 1717 ...