Carrier 17EX specifications Start-Up/Shutdown, Recycle Sequence Fig

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, or DURATION.

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 Ð 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 con®gured 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 ¯ow switches, and waits until the WATER FLOW VERIFY TIME (operator con®g- ured, default 5 minutes) to con®rm ¯ow. See the SERVICE1 screen or Table 2, Example 8. After ¯ow is veri®ed, 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 veri®ed, the PIC waits 10 seconds, and then the compressor start relay (1CR) is energized to start the compressor.

LEGEND

AÐ START INITIATED Ð Prestart checks made; chilled water pump started.

BÐ Condenser water pump started (5 seconds after A).

CÐ Water ¯ows veri®ed (one minute to 5 minutes maximum after A). Chilled water temperature checked against control point. Guide vanes checked for closure. Oil pumps started; tower fan control enabled.

DÐ Oil pressure veri®ed (for compressor, 15 seconds minimum, 300 seconds maximum, after C; for gear, within 30 seconds after C).

EÐ 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.

FÐ SHUTDOWN INITIATED Ð Compressor motor stops, guide vanes close, compressor ontime and service ontime stops, stop- to-start inhibit timer starts.

GÐ After the post-lube period, oil and evaporator pumps deener- gized. Post-lube con®gurable to between one and 5 minutes after Step F.

O/A Ð Restart permitted (both inhibit timers expired) (minimum of 15 minutes after E; minimum of 1 minute after F).

Fig. 22 Ð Control Sequence

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