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7. Press SELECT to access the holiday table. The LID
screen now shows the holiday start month and day, and
how many days the holiday period will last. See Fig. 24.
8. Press NEXT or PREVIOUS to highlight HOLIDAY
START MONTH, START DAY,orDURATION.
9. Press SELECT to modify the month, day, or
duration.
10. Press INCREASE or DECREASE to change the se-
lected value.
11. Press ENTER to save the changes.
12. Press EXIT to return to the previous menu.
START-UP/SHUTDOWN/
RECYCLE SEQUENCE (Fig. 22)
Local Start-Up —
Local start-up (or a manual start-up)
is initiated by pressing the LOCAL
menu softkey which is
on the default LID screen. Local start-up can proceed if the
OCCUPIED ? parameter on the STATUS01 table is set to
YES and after the internal 15-minute start-to-start timer and
the stop-to-start inhibit timer have expired.
The CHILLER START/STOP parameter on the STA-
TUS01 screen may be overridden to start, regardless of the
time schedule, in order to start the chiller locally. Also, the
remote contacts may be enabled through the LID and closed
to initiate a start-up.
Whenever the chiller is in LOCAL control mode, the PIC
waits for the current time to coincide with an occupied time
period as configured in the local time schedule (OCCPC01S)
and for the remote contacts to close, if enabled. The PIC
then performs a series of pre-start checks to verify that all
pre-start alerts and safeties are within the limits shown in
Table 3. The RUN STATUS line on the STATUS01 screen
now reads STARTUP.
If the checks are successful, the chilled water/brine pump
relay is energized. Five seconds later, the condenser pump
relay is energized. One minute later the PIC monitors the
chilled water and condenser water flow switches, and waits
until the WATER FLOW VERIFY TIME (operator config-
ured, default 5 minutes) to confirm flow. See the SERVICE1
screen or Table 2, Example 8.After flow is verified, the chilled
water/brine temperature is compared to WATER/BRINE CON-
TROL POINT plus DEADBAND. If the temperature is less
than or equal to this value, the PIC turns off the condenser
pump relay and goes into a RECYCLE mode.
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 6% open, the start-up waits
until the PIC closes the vanes. If the vanes are closed, and
the oil pump pressure is less than 3 psid (21 kPad), the oil
pump relay is then energized. The PIC then waits a mini-
mum of 15 seconds (maximum 5 minutes) to verify that the
compressor oil pressure (OIL PRESSURE on the STA-
TUS01 screen) has reached 15 psid (103 kPad). At the same
time, the PIC waits up to 30 seconds to verify that the gear
oil pressure (GEAR OIL PRESSURE on the STATUS04
screen) has reached 24 psi (166 kPa). After the oil pressures
are verified, the PIC waits 10 seconds, and then the
compressor start relay (1CR) is energized to start the
compressor.
LEGEND
A—START INITIATED — Prestart checks made; chilled water
pump started.
B—Condenser water pump started (5 seconds after A).
C—Water flows verified (one minute to 5 minutes maximum
afterA).Chilledwater temperaturecheckedagainst controlpoint.
Guide vaneschecked for closure.Oil pumps started;tower fan
control enabled.
D—Oil pressure verified (for compressor, 15 seconds minimum,
300 seconds maximum, after C; for gear, within 30 seconds
after C).
E—Compressor motor starts, compressor ontime and service
ontime starts, 15-minute inhibit timer starts (10 seconds
after D). Start-in-12 hours counter advances by one.
F—SHUTDOWN INITIATED — Compressor motor stops, guide
vanesclose, compressorontime andservice ontimestops,stop-
to-start inhibit timer starts.
G—After the post-lube period, oil and evaporator pumps deener-
gized. Post-lube configurable to between one and 5 minutes
after Step F.
O/A — Restart permitted (both inhibit timers expired) (minimum of
15 minutes after E; minimum of 1 minute after F).
Fig. 22 — Control Sequence
43