Carrier 19XR Start-up, Operation And Maintenance Instructions Manual

Also see for HERMETIC CENTRIFUGAL LIQUID CHILLERS 19XR: User manual Start-up and service instructions Installation instructions Product data Installation instructions

Contents

Carrier 19XR Start-up, Operation And Maintenance Instructions Manual Manual pdf 44 page image

START-UP/SHUTDOWN/RECYCLESEQUENCE (Fig. 23)Local Start-Up — Local start-up (or a manual start-up)is initiated by pressing the LOCAL menu softkey on thedefault CVC screen. Local start-up can proceed when thechiller schedule indicates that the current time and date havebeen established as a run time and date, and after the inter-nal 15-minute start-to-start and the 1-minute stop-to-startinhibit timers have expired. These timers are represented inthe START INHIBIT TIMER and can be viewed on the MAIN-STAT screen and DEFAULT screen. The timer must expirebefore the chiller will start. If the timers have not expiredthe RUN STATUS parameter on the MAINSTAT screen nowreads TIMEOUT.NOTE: The time schedule is said to be ‘‘occupied’’ if theOCCUPIED ? parameter on the MAINSTAT screen is set toYES. For more information on occupancy schedules, see thesections on Time Schedule Operation (page 19), OccupancySchedule (page 32), and To Prevent Accidental Start-Up(page 59), and Fig. 17.If the OCCUPIED ? parameter on the MAINSTAT screenis set to NO, the chiller can be forced to start as follows.From the default CVC screen, press the MENU andSTATUS softkeys. Scroll to highlight MAINSTAT. Pressthe SELECT softkey. Scroll to highlight CHILLER START/STOP. Press the START softkey to override the scheduleand start the chiller.NOTE: The chiller will continue to run until this forced startis released, regardless of the programmed schedule. Torelease the forced start, highlight CHILLER START/STOP fromthe MAINSTAT screen and press the RELEASE softkey.This action returns the chiller to the start and stop timesestablished by the schedule.The chiller may also be started by overriding the time sched-ule. From the default screen, press the MENU andSCHEDULE softkeys. Scroll down and select the currentschedule. Select OVERRIDE, and set the desired overridetime.Another condition for start-up must be met for chillers thathave 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. Scrolldown the STATUS01 screen to highlight REMOTE CON-TACTS INPUT and press the SELECT softkey. Then, pressthe CLOSE softkey. To end the override, select REMOTECONTACTS INPUT and press the RELEASE softkey.Once local start-up begins, the PIC II performs a series ofpre-start tests to verify that all pre-start alerts and safetiesare within the limits shown in Table 3. The RUN STATUSparameter on the MAINSTAT screen line now readsPRESTART. 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 linenow reads STARTUP.Five seconds later, the condenser pump relay energizes.Thirty seconds later the PIC II monitors the chilled waterand condenser water flow devices and waits until theWATER FLOW VERIFY TIME (operator-configured, default5 minutes) expires to confirm flow. After flow is verified, thechilled water temperature is compared to CONTROL POINTplus 1/2 CHILLED WATER DEADBAND. If the temperatureis less than or equal to this value, the PIC II turns off thecondenser pump relay and goes into a RECYCLE mode.If the water/brine temperature is high enough, the start-upsequence continues and checks the guide vane position. Ifthe guide vanes are more than 4% open, the start-up waitsuntil the PIC II closes the vanes. If the vanes are closed andthe oil pump pressure is less than 4 psi (28 kPa), the oilpump 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 waits40 seconds, and the compressor start relay (1CR) energizesto start the compressor.Compressor ontime and service ontime timers start, andthe compressor starts in 12 hours counter and the number ofstarts over a 12-hour period counter advance by one.Failure to verify any of the requirements up to this pointwill result in the PIC II aborting the start and displaying theapplicable pre-start mode of failure on the CVC default screen.A pre-start failure does not advance the starts in 12 hourscounter. Any failure after the 1CR relay has energizedresults in a safety shutdown, advances the starts in the12 hours counter by one, and displays the applicable shut-down status on the CVC display.A — START INITIATED — Prestart checks made; evaporatorpump started.B — Condenser water pump started (5 seconds after A).C — Water flows verified (30 seconds to 5 minutes maximumafter 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 secondsmaximum after C).E — Compressor motor starts, compressor ontime and serviceontime start, 15-minute inhibit timer starts (10 secondsafter D), total compressor starts advances by one, and thenumber 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-minuteinhibit timer starts.G — Oil pump and evaporator pumps deenergized (60 secondsafter F). Condenser pump and tower fan control may con-tinue to operate if condenser pressure is high. Evaporatorpump may continue if in RECYCLE mode.O/A — Restart permitted (both inhibit timers expired: minimum of15 minutes after E; minimum of 1 minute after F).Fig. 23 — Control Sequence44