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Table 23 — Operating Modes
MODE NO. ITEM EXPANSION DESCRIPTION
01
FSM CONTROLLING CHILLER Flotronic™ System Manager (FSM) is controlling the chiller.
02
WSM CONTROLLING CHILLER Water System Manager (WSM) is controlling the chiller.
03
MASTER/SLAVE CONTROL Lead/Lag Chiller control is enabled.
04
LOW SOURCE PROTECTION Not currently supported.
05
RAMP LOAD LIMITED Ramp load (pulldown) limiting in effect. In this mode, the rate at which leaving
fluid temperature is dropped is limited to a predetermined value to prevent
compressor overloading. See CRMP set point in the Set Point Select (SLCT)
section of the Configuration mode. The pulldown limit can be modified, if
desired, to any rate from 0.2° F to 2° F (0.1° to 1° C)/minute.
06
TIMED OVERRIDE IN EFFECT Timed override is in effect. This is a 1 to 4 hour temporary override of the
programmed schedule, forcing unit to Occupied mode. Override can be
implemented with unit under Local (Enable) or CCN control. Override
expires after each use.
07
LOW COOLER SUCTION TEMP A Circuit A capacity may be limited due to operation of this mode. Control will
attempt to correct this situation for up to 10 minutes before shutting the cir-
cuit down. The control may decrease capacity when attempting to correct
this problem. See Alarms and Alerts section for more information.
08
LOW COOLER SUCTION TEMP B Circuit B capacity may be limited due to operation of this mode. Control will
attempt to correct this situation for up to10 minutes before shutting the cir-
cuit down. The control may decrease capacity when attempting to correct
this problem. See Alarms and Alerts section for more information.
09
SLOW CHANGE OVERRIDE Slow change override is in effect. The leaving fluid temperature is close to
and moving towards the control point.
10
MINIMUM OFF TIME ACTIVE Chiller is being held off by Minutes Off Time (DELY) found under Options 2
(OPT2) section of Configuration mode.
11
LOW SUCTION SUPERHEAT A Circuit A capacity may be limited due to operation of this mode. Control will
attempt to correct this situation for up to 5 minutes before shutting the cir-
cuit down. See Alarms and Alerts section for more information.
12
LOW SUCTION SUPERHEAT B Circuit B capacity may be limited due to operation of this mode. Control will
attempt to correct this situation for up to 5 minutes before shutting the cir-
cuit down. See Alarms and Alerts section for more information.
13
DUAL SET POINT Dual set point mode is in effect. Chiller controls to CSP.1 during occupied
periods and CSP.2 during unoccupied periods. Both CSP.1 and CSP.2 are
located under COOL in the Set Point mode.
14
TEMPERATURE RESET Temperature reset is in effect. In this mode, chiller is using temperature
reset to adjust leaving fluid set point upward and is currently controlling to
the modified set point. The set point can be modified based on return fluid,
outdoor-air-temperature, space temperature, or 4 to 20 mA signal.
15
DEMAND LIMIT IN EFFECT Demand limit is in effect. This indicates that the capacity of the chiller
is being limited by demand limit control option. Because of this limitation,
the chiller may not be able to produce the desired leaving fluid temperature.
Demand limit can be controlled by switch inputs or a 4 to 20 mA signal.
16
COOLER FREEZE PROTECTION Cooler fluid temperatures are approaching the Freeze point (see Alarms
and Alerts section for definition). The chiller will be shut down when either
fluid temperature falls below the Freeze point.
17
LO TMP COOL/HI TMP HEAT Chiller is in Cooling mode and the rate of change of the leaving fluid is neg-
ative and decreasing faster than -0.5° F per minute. Error between leaving
fluid and control point exceeds fixed amount. Control will automatically
unload the chiller if necessary.
18
HI TMP COOL/LO TMP HEAT Chiller is in Cooling mode and the rate of change of the leaving fluid is positive
and increasing. Error between leaving fluid and control point exceeds fixed
amount. Control will automatically load the chiller if necessary to better match
the increasing load.
19
MAKING ICE Chiller is in an unoccupied mode and is using Ice Set Point 3 (CSP.3) to make
ice. The ice done input to the Energy Management Module (EMM) is open.
20
STORING ICE Chiller is in an unoccupied mode and is controlling to Cooling Set Point 2
(CSP.2). The ice done input to the Energy Management Module (EMM) is
closed.
21
HIGH SCT CIRCUIT A Chiller is in a cooling mode and the Saturated Condensing temperature read
by sensor T3 is greater than 140 F (60 C). No additional stages of capacity
will be added. Chiller may be unloaded if SCT continues to rise to avoid high-
pressure switch trips by reducing condensing temperature.
22
HIGH SCT CIRCUIT B Chiller is in a cooling mode and the Saturated Condensing temperature read
by sensor T4 is greater than 140 F (60 C). No additional stages of capacity
will be added. Chiller may be unloaded if SCT continues to rise to avoid high-
pressure switch trips by reducing condensing temperature.
