Carrier AquaEdge 19DV series, Управление, эксплуатация и устранение неисправностей

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Fig. 30 — Start-Up Sequence Screen
Table 12 — Pre-Start Alerts and Alarms
* Evap trip point = 33°F (0.6°C) (water) or EVAP REFRIG TRIPPOINT
(brine).
Chiller Shutdown Sequence
Chiller shutdown begins if any of the following occurs:
• Local OFF button is pressed
• A recycle condition is present (see the previous section)
• The time schedule has gone into unoccupied mode when in
either Network or Local Schedule control mode
• The chiller protective limit has been reached and chiller is
in alarm
• The start/stop status (CHIL_S_S) is overridden to stop
from the network when in Network mode
If the chiller is normally shut down from running, a soft-stop
shutdown will be performed. The soft-stop feature closes the
guide vanes of the compressor automatically if a non-alarm
stop signal occurs before the compressor motor is deenergized.
Any time the compressor is directed to STOP (except in the
cases of a fault shutdown), the guide vanes are directed to close
and VFD will be commanded to minimum speed for a variable
speed compressor. The compressor shuts off when any of the
following is true:
• PERCENT LOAD CURRENT (%) drops below the SOFT
STOP AMPS THRESHOLD
• ACTUAL GUIDE VANE POSITION drops below 4%
• Four minutes have elapsed since the stop was initialized
When any of these conditions is true, the shutdown sequence
stops the compressor by deactivating the compressor start re-
lay. The guide vanes are then commanded to the fully closed
position. The refrigerant pump relay will be turned off after
120 seconds post-lube.
Finally, the chilled water/brine pump and condenser water
pump are shut down.
Refrigerant Lubrication Control
As part of the pre-lube process, the Bearing Input Refrigerant
Pressure is compared to the Bearing Output Refrigerant Pressure.
If the Bearing Input Refrigerant Pressure (BRGI_P) is less than 5
psi (34.5 kPa) higher than the Bearing Output Refrigerant Pressure
(BRGO_P), the liquid level in the condenser is checked. If the liq-
uid level switch is ON, refrigerant is pumped from the evaporator
to the condenser until the liquid level switch is OFF. Once the con-
denser liquid level is satisfied, the Evaporator Temperature
(EVAP_T) is compared to the Leaving Condenser Water Tem-
perature. When the Evaporator Temperature is 10 degrees higher
than the Leaving Condenser Water Temperature or the Refrigerant
Lubrication Pressure Difference is at least 12 psi, the refrigerant
pump remains on the compressor is turned ON.
The refrigerant pump relay is always ON when the compressor
is running.
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 13.
Table 13 — Set Point Determination
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 con-
trol 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.
PRE-START ALERT
CONDITION
STATE
NO.
ALARM OR
ALERT
STARTS IN 12 HOURS >= 8 100 Alert
CONDENSER PRESSURE >=
COND PRESS OVERRIDE – 20 psi
102 Alert
Number of recycle restart in the last 4 hours
is greater than 5
103 Alert
COMP BEARING TEMP >= COMP BEAR-
ING ALERT – 10°F (5.5°C)
230 Alarm
COMP MOTOR WINDING TEMP >=
MOTOR TEMP OVERRIDE – 10°F (5.5°C)
231 Alarm
COMP DISCHARGE TEMP >= COMP DIS-
CHARGE ALERT– 10°F (5.5°C)
232 Alarm
EVAP_SAT < Evap trip point* +
EVAP OVERRIDE DELTA T
or
EVAP REFRIG LIQUID TEMP < Evap trip
point* + EVAP OVERRIDE DELTA T
233 Alarm
ACTUAL LINE VOLTAGE <=
UNDERVOLTAGE THRESHOLD
234 Alarm
ACTUAL LINE VOLTAGE >=
OVERVOLTAGE THRESHOLD
235 Alarm
Guide vane 1 has not been calibrated
successfully
236 Alarm
Prestart Failure - No Power Supply (If Water
Verification Time has passed after Request
To Start has been sent and there has not
been received a Permission To Start)
237 Alarm
Guide vane 2 has not been calibrated
successfully
238 Alarm
EWT
CONTROL
OPTION
HEAT/COOL MODE
COOLING HEATING
Disabled Cooling LCW Set Point Heating LCDW Set Point
Enabled Cooling ECW Set Point Heating ECDW Set Point