Control Points - Carrier AquaEdge 19DV Operation And Troubleshooting

CONTROL VALVE
STATUS
EVAPORATOR CONDENSER
CHILLER OFF Close
PRE-START
Close
PRE-CHARGE Close
PRE-LUBE Open
COMPRESSOR RUN Open
POST-LUBE Close
NOTES:
1. Upon competition of post-lube the chiller is off and the sequence
can be started over.
2. Evaporator Control Valve:
Close = source refrigeration pump from high side float chamber
Open = source refrigeration pump from evaporator

Control Points

SET POINT
The set point can be configured at the Setpoint menu ("USER"
access level).
The set point is determined by the heat/cool mode, EWT (en-
tering water temperature) option, and ice build option. See
Table 14.
Table 14 — Set Point Determination
EWT
CONTROL
COOLING
OPTION
Disabled Cooling LCW Set Point
Enabled Cooling ECW Set Point
NOTES:
1. The ice build option is disabled when heat/cool mode is set to
Heating.
2. When the ice build option is enabled and ice build is active, the
control point is the Ice Build Set Point and the controlled water tem-
perature is the leaving chilled water temperature.
CONTROL POINT TEMPERATURE
Capacity control is based on achieving and maintaining a control
point temperature, which is the sum of a valid set point (from the
SETPOINT screen) and a temperature reset value. In Cooling
mode, the control point temperature is equal to the set point plus
temperature reset. In Heating mode, the control point temperature
is equal to the set point minus temperature reset.
The control point can be viewed directly on the main screen or
the General Parameters menu.
TEMPERATURE RESET
Three types of chilled water or brine reset are available and can
be viewed or modified on the Reset Configuration screen.
The default screen indicates when the chilled water reset is ac-
tive. The control point Reset on the General Parameters screen
indicates the amount of reset.
To activate a reset type, access the Reset Configuration
(RESETCFG) screen and input all configuration informa-
tion for that reset type.
Table 13 — Lube Assembly Control Valve (CV)
Close Chiller is off - a start is to be initiated to change state.
Refrigerant pump turns on if pump differential pressure is less than 5 psig - if differential
Open
pressure higher Alarm 285 will be displayed.
Objective is the charge the high side float with refrigerant. If high side float chamber level switch is
not closed the refrigerant will be pumped from the evaporator to the high side float chamber until
Open the high side float chamber level switch is satisfied. If level switch is not closed after 10 minutes
alert 163 will be active and startup will stop. Once high side float chamber switch is satisfied the
pre-charge process pumping liquid to the high side float chamber will continue for 1 minute.
Upon completion of the pre-charge state the controls will verify that the pump refrigerant
differential pressure is greater than the limit (typically 8 psig). If not alarm 285 will be
Close
activated. Pre-lube will provide refrigerant to the compressor bearings from the high side float
chamber. Its duration is 10-20 seconds.
Refrigerant pump is continuously on and refrigerant is provided to compressor bearings from
Close
high side float chamber.
Upon compressor stop a post-lube cycle of 30 seconds is completed before the refrigerant
Close pump is stopped. During post-lube the bearings are supplied with refrigerant from the
evaporator.
HEAT/COOL MODE
HEATING
Heating LCDW Set Point
Heating ECDW Set Point
DESCRIPTION
3. Condenser Control Valve:
Close = refrigerant pump discharge to compressor bearings
Open = refrigerant pump discharge to high side float chamber
Reset Type 1: 4 to 20 mA Temperature Reset
Reset Type 1 is an automatic reset utilizing a 4 to 20 mA analog
input signal provided from any external sensor, controller, or
other device which is appropriately configured. For this type,
Degrees Reset At 20 mA is configured in the RESETCFG table.
Reset Type 2: Remote Temperature Reset
Reset Type 2 is an automatic water temperature reset based on
a remote temperature sensor input signal. This function can be
accessed by setting the following configurations:
1. Configure the remote temperature at which no reset occurs
(Remote temp  NO RESET).
2. Configure the remote temperature at which full reset
occurs (Remote temp  FULL RESET).
3. Enter the amount of reset (Deg Reset Water DT Full).
Reset Type 3: Controlled Water Temp Delta Reset
Reset Type 3 is an automatic controlled water temperature re-
set based on heat exchanger temperature difference. This func-
tion can be accessed by setting the following configurations:
1. Configure the controlled water temperature delta T at which
no reset occurs (Controlled Water DELTA T  NO RESET).
2. Configure the controlled water temperature delta T at
which full reset occurs (Controlled Water DELTA T 
FULL RESET).
3. Enter the amount of reset (Deg Reset Water DT Full).
CAPACITY CONTROL
Capacity control provides chilled or condenser water tempera-
ture control by modulating the position of the inlet guide vane 1
and VFD speed for variable speed compressors.
For 19DV when increased capacity is needed, the control will
first try to increase IGV TARGET POSITION if it has not
reached the travel limit; if the travel limit has been reached, the
control increases VFD TARGET SPEED. If decreased capacity
is needed, the control first tries to decrease VFD TARGET
SPEED if it has not reached the minimum VFD speed; if the
minimum VFD speed has been reached, the control decreases
IGV TARGET POSITION instead. See Fig. 31.
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