23
are listed in Table 20. These values depend on the Evaporator
Fluid Type and the Brine Freeze Setpoint (see Chilled Water
Fluid Type Selection on page 25).
Table 20 — Evaporator Fluid Set Point Limits
*The minimum set point for brine applications is related to the brine
freeze set point. The set point is limited to be no less than the brine
freeze set point + 4° F (2.2° C).
CURRENT OPERATING SET POINT — Depending on
the current operation type, the active set point can be se-
lected manually in the Main Menu, with the dry user con-
tacts, with network commands (CCN or BACnet), or auto-
matically with the set point time schedule (Occupancy
Schedule 2).
Set points can be selected manually through the main
interface when the unit is in Local operating type, through
contacts when the unit is in Remote operating type, or
through the RS485 bus when unit is in CCN mode.
Set points can also be selected automatically through a
set point time schedule: when the period is occupied Cool-
ing Setpoint 1 will be activated, and when the period is
Unoccupied Cooling Setpoint 2 will be active. When in lo-
cal operating type, time schedule is available if the Set-
point Select Variable is set to AUTO (see below). In re-
mote operating type, the AUTO mode will be available un-
less the dual set point control through contacts has already
been selected. In CCN mode, the set point selection al-
ways depends on the time schedule. The set point can be
forced through the SP_OCC CCN point (0 = Occupied =
Cooling Setpoint 1, 1 = Unoccupied = Cooling Setpoint 2).
Set point selection offers three different control options
(Main Menu General Parameters Setpoint Select): Auto,
Setpoint 1, and Setpoint 2.
• 0 = Auto: The active cooling set point will be determined
by the configured Occupancy Schedules. See the Defin-
ing Occupancy Schedule section for details on setting the
schedules. Depending on the Ice Storage configuration
and ice contact state, the active set point may alternately
be set to the Cooling Ice Setpoint.
• 1 = Setpoint 1: The active cooling set point will be Cool-
ing Setpoint 1 defined in the set point table.
• 2 = Setpoint 2: The active cooling set point will be Cool-
ing Setpoint 2 defined in the set point table. Depending
on the Ice Storage configuration and ice contact state, the
active set point may alternately be set to the Cooling Ice
Setpoint.
SETPOINT OCCUPANCY — Setpoint Occupancy is the de-
fault configuration for the Setpoint Select variable. When Set-
point Select (Main Menu General Parameters Setpoint
Select) is configured to 0 (Auto), the unit’s active set point is
based on the programmed occupancy schedules. Under Time
Schedule 1 (OCCPC01S), the unit controls to Cooling Set
Point 1 (csp1) during the occupied periods. If the Time Sched-
ule 2 (OCCPC02S) is in use, the unit’s active set point is based
on Cooling Set Point 1 (csp1) (Main Menu Setpoint Table
Cooling Setpoint 1) during the occupied period and Cooling
Set Point 2 (csp2) (Main Menu Setpoint Table Cooling
Setpoint 2) during the unoccupied period. The two schedules
are used together to determine periods when the chiller will be
controlling to Setpoint 1, Setpoint 2, or Off.
See Table 21 for details on how the active cooling set point is
determined based on unit operating type and parameter settings.
DEFINING OCCUPANCY SCHEDULE — Two internal
Time Schedules are available and must be field programmed.
Occupancy Schedule 1 (OCCPC01S) is used for single set
point On/Off control. Occupancy Schedule 2 (OCCPC02S) is
used in combination with OCCPC01S for dual set point On/Off
and Occupied/Unoccupied set point control. To access the
Schedule screens, go to Main Menu Configuration Menu
Schedule Menu.
If the chiller is to be controlled to a single set point, use
Schedule 1 (OCCPC01S). This type of schedule will start and
stop the machine only. During the unoccupied times, the chiller
will be off. The unit start/stop schedule OCCPC01S has a de-
fault setting of always occupied. If the chiller is to be controlled
to 2 set points, occupied and unoccupied, also use Schedule 2
(OCCPC02S). Cooling Setpoint 1 will be active during occu-
pied periods, and Cooling Setpoint 2 will be active during un-
occupied periods.
Table 21 — Active Cooling Set Point Parameters
* Ice Storage Configuration and Ice Done Contact apply only to units
with energy management module (EMM).
Set Point
Limits
EVAPORATOR FLUID TYPE (flui_typ)
1 = Water 2 = Medium Brine 3 = Low Brine
Minimum* 38 F (3.3 C) N/A N/A
Maximum 60 F (15.5 C) N/A N/A
OPERATING
TYPE
PARAMETER STATUS
ACTIVE SETPOINT
Setpoint
Selection
Ice Storage
Configuration*
Ice Done
Contact*
Setpoint
Switch
Schedule 2 Status
Local
sp-1 Default Any Any Default Cooling Setpoint 1
sp-2 No Any Any Default Cooling Setpoint 2
sp-2 Yes Closed Any N/A Cooling Setpoint 2
sp-2 Yes Open Any N/A Cooling Ice Setpoint
automatic Default Any Any Occupied Cooling Setpoint 1
automatic No Any Any Unoccupied Cooling Setpoint 2
automatic Yes Closed Any Unoccupied Cooling Setpoint 2
automatic Yes Open Any Unoccupied Cooling Ice Setpoint
Remote
Default Default Any Open Default Cooling Setpoint 1
Default No Any Closed Default Cooling Setpoint 2
N/A Yes Closed Closed N/A Cooling Setpoint 2
Default Yes Open Closed Default Cooling Ice Setpoint
Network
Default Default Any Any Occupied Cooling Setpoint 1
Default Default Any Any Unoccupied Cooling Setpoint 2
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