51
6 - START-UP/SHUTDOWN/RECYCLE SEQUENCE
(FIG. 15)
6.1 - Local start-up
Local start-up (or a manual start-up) is initiated by pressing
the
LoCAL
menu softkey on the default ICVC screen.
Local start-up can proceed when the chiller schedule
indicates that the CURRENT TIME and CURRENT
DATE have been established as a run time and date, and
after the internal timers have expired. The timers include a
15-minute start-to-start timer and a 1-minute stop-to-start
timer, which together serve to prevent excessive cycling and
abuse of the motor. The value of these timers is displayed
as START INHIBIT TIMER and can be viewed on the
MAINSTAT and DEFAULT screens. Both timers must
expire before the chiller will start. If the timers have not
expired, the RUN STATUS parameter on the MAINSTAT
screen will read TIMEOUT.
note:
The time schedule is said to be “occupied” if the
OCCUPIED ?
parameter on the MAINSTAT screen is set to
YES. For more information on occupancy schedules, see the
sections on Time Schedule Operation (page 19), Occupancy
Schedule (page 35), and To Prevent Accidental Start-Up
(page 53), and Fig. 8.
If the
OCCUPIED ?
parameter on the MAINSTAT screen is
set to NO, the chiller can be forced to start as follows. From
the default ICVC screen, press the
MenU
and
StAtUS
softkeys. Scroll to highlight MAINSTAT. Press the
SeLeCt
softkey. Scroll to highlight CHILLER START/STOP. Press
the
StARt
softkey to override the schedule and start the
chiller.
note:
The chiller will continue to run until this forced start
is released, regardless of the programmed schedule. To
release the forced start, highlight
CHILLER START/STOP
from the MAINSTAT screen and press the
ReLeASe
softkey. This action returns the chiller to the start and stop
times established by the schedule.
The chiller may also be started by overriding the time
schedule. From the default screen, press the
MenU
and
SCHeDULe
softkeys. Scroll down and select the current
schedule. Select OVERRIDE, and set the desired override
time.
Another condition for start-up must be met for chillers that
have the
REMOTE CONTACTS OPTION
on the EQUIP-
MENT SERVICE screen set to ENABLE. For these chillers,
the
REMOTE START CONTACT
parameter on the MAIN-
STAT screen must be CLOSED. From the ICVC default
screen, press the
MenU
and
StAtUS
softkeys. Scroll to
highlight MAINSTAT and press the
SeLeCt
softkey.
Scroll down the MAINSTAT screen to highlight
REMOTE
START CONTACT
and press the
SeLeCt
softkey. Then,
press the
CLoSe
softkey. To end the override, select
REMOTE CONTACTS INPUT
and press the
ReLeASe
softkey.
Once local start-up begins, the PIC III performs a series of
pre-start tests to verify that all pre-start alerts and safeties
are within the limits shown in Table 6. The
RUN STATUS
parameter on the MAINSTAT screen line now reads PRE-
START. If a test is not successful, the start-up is delayed or
aborted. If the tests are successful, the CHILLED WATER
PUMP relay energises, and the RUN STATUS line now
reads STARTUP. See Table 8.
Five seconds later, the CONDENSER WATER PUMP relay
energises. Thirty seconds later, the PIC III monitors the
chilled water and condenser water flow devices and waits until
the
WATER FLOW VERIFY TIME
(operator-configured,
default 5 minutes) expires to confirm flow. After flow is
verified, the chilled water temperature is compared to
CONTROL POINT
plus
1/2 CHILLED WATER DEAD-
BAND
. If the temperature is less than or equal to this value,
the PIC III turns off the CONDENSER WATER PUMP
relay and goes into a RECYCLE mode.
note:
The 19XRV units are not available with factory-
installed chilled water or condenser water flow devices
(available as an accessory for use with the CCM control
board).
If the water/brine temperature is high enough, the start-up
sequence continues and checks the guide vane position. If
the guide vanes are more than 4% open, the start-up is
delayed until the PIC III closes the vanes. If the vanes are
closed and the oil pump pressure is less than 8 kPa, the oil
pump relay energises. The PIC III then waits until the oil
pressure (
OIL PRESS VERIFY TIME
, operator-configured,
default of 40 seconds) reaches a maximum of 14 kPa.
After oil pressure is verified, the PIC III waits 40 seconds,
and the VFD energises to start the compressor.
Table 8 — Prestart checks
QUANTITY CHECKED
REQUIREMENT
ALERT STATE IF FALSE
STARTS IN 12 HOURS
< 8 (not counting recycle restarts or auto restarts after power failure) ALERT is cleared
once RESET is pressed.
100
COMP THRUST BRG TEMP
< [COMP THRUST BRG ALERT] 5.6°C
101
COMP MOTOR WINDING TEMP
< [COMP MOTOR TEMP OVERRIDE] 5.6°C
102
COMP DISCHARGE TEMP
< [COMP DISCHARGE ALERT] 5.6°C
103
EVAPORATOR REFRIG TEMP
< [EVAP REFRIG TRIPPOINT] + [REFRIG OVERRIDE DELTA T]
104
OIL SUMP TEMP
< 65.5°C or <[EVAPORATOR REFRIG TEMP] + 27.8°C
105
CONDENSER PRESSURE
< [COND PRESS OVERRIDE] 138 kPa and < 1000 kPa
106
PERCENT LINE VOLTAGE
< [Undervoltage Threshold]
107
PERCENT LINE VOLTAGE
> [Overvoltage Threshold]
108
ACTUAL GUIDE VANE POS
Controls test guide vane calibration must be performed
109
RECTIFIER TEMPERATURE
< RECTIFIER TEMP OVERRIDE –11.1 K
110
INVERTER TEMPERATURE
< INVERTER TEMP OVERRIDE – 11.1 K
111