Carrier 30GTN Service And Troubleshooting Manual page 42

MODE NO.
01 FSM CONTROLLING CHILLER
02 WSM CONTROLLING CHILLER
03 MASTER/SLAVE CONTROL
04 LOW SOURCE PROTECTION
05 RAMP LOAD LIMITED
06 TIMED OVERRIDE IN EFFECT
07 LOW COOLER SUCTION TEMP A
08 LOW COOLER SUCTION TEMP B
09 SLOW CHANGE OVERRIDE
10 MINIMUM OFF TIME ACTIVE
11 LOW SUCTION SUPERHEAT A
12 LOW SUCTION SUPERHEAT B
13
14 TEMPERATURE RESET
15 DEMAND LIMIT IN EFFECT
16 COOLER FREEZE PROTECTION
17 LO TMP COOL/HI TMP HEAT
18 HI TMP COOL/LO TMP HEAT
Table 22 — Operating Modes
ITEM EXPANSION
DUAL SETPOINT
DESCRIPTION
Flotronic™ System Manager (FSM) is controlling the chiller
Water System Manager (WSM) is controlling the chiller
Lead/Lag Chiller control is enabled.
Not currently supported.
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 de-
sired, to any rate from 0.2° F to 2° F (0.1 to 1 C)/minute.
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 (En-
able) or CCN control. Override expires after each use.
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 circuit down. The control may decrease ca-
pacity when attempting to correct this problem. See Alarms and
Alerts section for more information.
Circuit B 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 circuit down. The control may
decrease capacity when attempting to correct this problem.
See Alarms and Alerts section for more information.
Slow change override is in effect. The leaving fluid temperature
is close to and moving towards the control point.
Chiller is being held off by Minutes Off Time (DELY) found un-
der Options 2 (OPT2) section of Configuration mode.
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 circuit down. See Alarms and Alerts section
for more information.
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 circuit down. See Alarms and
Alerts section for more information.
Dual set point mode is in effect. Chiller controls to CSP.1 dur-
ing occupied periods and CSP.2 during unoccupied periods.
Both CSP.1 and CSP.2 are located under COOL in the Set
Point mode.
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.
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 de-
sired leaving fluid temperature. Demand limit can be controlled
by switch inputs or a 4 to 20 mA signal.
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.
Chiller is in Cooling mode and the rate of change of the leaving
fluid is negative 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.
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.
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