Chiller Shutdown Sequence; Refrigerant Lubrication Control - Carrier AquaEdge 19DV Operation And Troubleshooting

STARTS IN 12 HOURS >= 8
CONDENSER PRESSURE >= COND PRESS OVERRIDE – 20 psi
Number of recycle restart in the last 4 hours is greater than 5
COMP BEARING TEMP >= COMP BEARING ALERT – 10°F (5.5°C)
COMP MOTOR WINDING TEMP >= MOTOR TEMP OVERRIDE – 10°F (5.5°C)
COMP DISCHARGE TEMP >= COMP DISCHARGE ALERT– 10°F (5.5°C)
EVAP_SAT < Evap trip point* + EVAP OVERRIDE DELTA T
or
EVAP REFRIG LIQUID TEMP < Evap trip point* + EVAP OVERRIDE DELTA T
ACTUAL LINE VOLTAGE <= UNDERVOLTAGE THRESHOLD
ACTUAL LINE VOLTAGE >= OVERVOLTAGE THRESHOLD
Guide vane 1 has not been calibrated successfully
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)
Guide vane 2 has not been calibrated successfully
* Evap trip point = 33°F (0.6°C) (water) or EVAP REFRIG TRIPPOINT
(brine).
START-UP
One second after the successful pre-start check, the chilled wa-
ter and condenser water pump relays are energized.
Five seconds later, the control monitors the chilled water and
condenser water flow devices and waits until the WATER
FLOW VERIFY TIME (service-configured, default 5 minutes)
expires to confirm water flow.
After water flow is verified, the water temperature is compared to
CONTROL POINT + / CHILLED WATER DEADBAND. If
1
2
the temperature is less than or equal to this value, the control turns
off the condenser pump relay and goes into RECYCLE mode.
If the RECYCLE condition is not satisfied, the start-up se-
quence continues and checks the guide vane position. The
guide vanes are opened to the initial position specified with
GV1 Closure at Startup in the Option Configuration menu.
If an EC/HGBP or economizer damper valve is equipped and
enabled, the control checks that the position of these valves is
fully closed.
If the vanes and valves positions are verified and the refriger-
ant pump pressure difference is less than 2.5 psi (17.2 kPa), the
refrigerant pump relay is energized.
The control then waits the operator-configured verification time
(default 40 seconds) for the refrigerant pressure difference to reach
12 psi. After the refrigerant pressure is verified, the control waits
20 seconds for prelube, and after achieving and maintaining the
refrigerant pressure, the compressor start relay energizes to start
the compressor.

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
Table 12 — Pre-Start Alerts and Alarms
PRE-START ALERT CONDITION STATE NO.
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

The lube sled assembly under the 19DV condenser barrel man-
ages the lubricating refrigerant supply to the compressor bear-
ings. As part of startup/shutdown, 19DV goes through the stages
identified in Table 13.
Essentially the evaporator and condenser control valves are po-
sitioned to charge the high side float chamber with liquid re-
frigerant from the cooler or to supply liquid refrigerant to the
bearings from the high side float chamber.
For startup the refrigerant pump delta difference must at least
be 8 psig (55.2 kPa).
If it is the first time that the unit is being started, then the con-
trols will perform a 30 minute pre-lubrication. Status flag for
this is found in the Quick Calibration menu.The refrigerant
pump relay is always ON when the compressor is running.
17
ALARM OR ALERT
100 Alert
102 Alert
103 Alert
230 Alarm
231 Alarm
232 Alarm
233 Alarm
234 Alarm
235 Alarm
236 Alarm
237 Alarm
238 Alarm