Start-Up/Shutdown/Recycle; Sequence; Local Start-Up - Carrier 19XR Start-Up, Operation And Maintenance Instructions Manual

START-UP/SHUTDOWN/RECYCLE

SEQUENCE (Fig. 23)
Local Start-Up —
Local start-up (or a manual start-up)
is initiated by pressing the LOCAL menu softkey on the
default CVC screen. Local start-up can proceed when the
chiller schedule indicates that the current time and date have
been established as a run time and date, and after the inter-
nal 15-minute start-to-start and the 1-minute stop-to-start
inhibit timers have expired. These timers are represented in
the START INHIBIT TIMER and can be viewed on the MAIN-
STAT screen and DEFAULT screen. The timer must expire
before the chiller will start. If the timers have not expired
the RUN STATUS parameter on the MAINSTAT screen now
reads 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 32), and To Prevent Accidental Start-Up
(page 59), and Fig. 17.
If the OCCUPIED ? parameter on the MAINSTAT screen
is set to NO, the chiller can be forced to start as follows.
From the default CVC 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 sched-
ule. 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 CONTACTS INPUT parameter on the MAIN-
STAT screen must be CLOSED. From the CVC default screen,
press the MENU and STATUS softkeys. Scroll to high-
light MAINSTAT and press the SELECT softkey. Scroll
down the STATUS01 screen to highlight REMOTE CON-
TACTS INPUT 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 II performs a series of
pre-start tests to verify that all pre-start alerts and safeties
are within the limits shown in Table 3. The RUN STATUS
parameter on the MAINSTAT screen line now reads
PRESTART. If a test is not successful, the start-up is de-
layed or aborted. If the tests are successful, the chilled water/
brine pump relay energizes, and the MAINSTAT screen line
now reads STARTUP.
Five seconds later, the condenser pump relay energizes.
Thirty seconds later the PIC II 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 DEADBAND. If the temperature
is less than or equal to this value, the PIC II 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 4% open, the start-up waits
until the PIC II closes the vanes. If the vanes are closed and
the oil pump pressure is less than 4 psi (28 kPa), the oil
pump relay energizes. The PIC II then waits until the oil pres-
sure (OIL PRESS VERIFY TIME, operator-configured,
default of 40 seconds) reaches a maximum of 18 psi
(124 kPa). After oil pressure is verified, the PIC II waits
40 seconds, and the compressor start relay (1CR) energizes
to start the compressor.
Compressor ontime and service ontime timers start, and
the compressor starts in 12 hours counter and the number of
starts over a 12-hour period counter advance by one.
Failure to verify any of the requirements up to this point
will result in the PIC II aborting the start and displaying the
applicable pre-start mode of failure on the CVC default screen.
A pre-start failure does not advance the starts in 12 hours
counter. Any failure after the 1CR relay has energized
results in a safety shutdown, advances the starts in the
12 hours counter by one, and displays the applicable shut-
down status on the CVC display.
A — START INITIATED — Prestart checks made; evaporator
pump started.
B — Condenser water pump started (5 seconds after A).
C — Water flows verified (30 seconds to 5 minutes maximum
after B). Chilled water temperatures checked against con-
trol point. Guide vanes checked for closure. Oil pump started;
tower fan control enabled.
D — Oil pressure verified (15 seconds minimum, 300 seconds
maximum after C).
E — Compressor motor starts, compressor ontime and service
ontime start, 15-minute inhibit timer starts (10 seconds
after D), total compressor starts advances by one, and the
number of starts over a 12-hour period advances by one.
F — SHUTDOWN INITIATED — Compressor motor stops, com-
pressor ontime and service ontime stops, and 1-minute
inhibit timer starts.
G — Oil pump and evaporator pumps deenergized (60 seconds
after F). Condenser pump and tower fan control may con-
tinue to operate if condenser pressure is high. Evaporator
pump may continue if in RECYCLE mode.
O/A — Restart permitted (both inhibit timers expired: minimum of
15 minutes after E; minimum of 1 minute after F).
Fig. 23 — Control Sequence
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