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

Also see for AquaEdge 19XRV series: Start-up, operation and maintenance instructions Start-up and service instructions Installation instructions Start-up, operation and maintenance instructions Start-up and service instructions

Contents

557.3.4 - Dual-temperature sensorsFor servicing convenience, there are sensors each on thebearing and motor temperature sensors. If one of the sensorsis damaged, the other can be used by simply moving a wire.The number terminal in the sensor terminal box is thecommon line. To use the second sensor, move the wirefrom the number 1 position to the number 3 position.7.4 - Checking pressure transducersThere are 6 factory-installed pressure transducers, withinputs available for optional cooler and condenser water-side differential pressure transducers. The ICVC softwarewill display a default reading of 179 kPa during start-up andoperation. An additional transducer, factory installed inthe bottom of the cooler barrel, will read as EVAPORATORSATURATION TEMP on the HEAT_EX DISPLAY screen.This provides additional protection against a loss of waterflow condition.These pressure transducers can be calibrated if necessary.It is not usually necessary to calibrate at initial start-up.However, at high altitude locations, it is necessary to cali-brate the transducers to ensure the proper refrigeranttemperature/pressure relationship. Each transducer issupplied with 5 V d.c. power from the CCM. If the powersupply fails, a transducer voltage reference alarm occurs. Ifthe transducer reading is suspected of being faulty, checkthe TRANSDUCER VOLTAGE REF supply voltage. Itshould be 5 V d.c. ± 0.5 V displayed in CONTROL TESTunder CCM PRESSURE TRANSDUCERS. If the TRANS-DUCER VOLTAGE REF is correct, the transducer shouldbe recalibrated or replaced.Also check that inputs on CCM J5-1 through J5-6 have notbeen grounded and are not receiving anything other than a4 to 0 mA signal.7.4.1 - Cooler/condenser pressure transducer and optionalwater-side flow device calibrationCalibration can be checked by comparing the pressurereadings from the transducer to an accurate refrigerationgage reading. These readings can be viewed or calibratedfrom the HEAT_EX screen on the ICVC. The transducercan be checked and calibrated at pressure points. Thesecalibration points are 0 kPa and between173 and 174 kPa.To calibrate these transducers:1. Shut down the compressor, cooler, and condenserpumps.note: There should be no flow through the heatexchangers.. Disconnect the transducer in question from its Schraderfitting for cooler or condenser transducer calibration.For oil pressure or flow device calibration, leave thetransducer in place.note: If the cooler or condenser vessels are at 0 kPaor are open to atmospheric pressure, the transducerscan be calibrated for zero without removing thetransducer from the vessel.3. Access the HEAT_EX screen and view the particulartransducer reading (the EVAPORATOR PRESSUREor CONDENSER PRESSURE parameter on theHEAT_EX screen). To calibrate oil pressure or liquid-side flow device, view the particular reading (CHILLEDWATER DELTA P and CONDENSER WATERDELTA P on the HEAT_EX screen, and OIL PUMPDELTA P on the COMPRESS screen). It should read0 kPa. If the reading is not 0 kPa, but within ± 35 kPa,the value may be set to zero by pressing the SeLeCtsoftkey while the appropriate transducer parameter ishighlighted on the ICVC screen. Then press the enteRsoftkey. The value will now go to zero. No high endcalibration is necessary for OIL PRESSURE DELTA Por flow devices.If the transducer value is not within the calibrationrange, the transducer returns to the original reading. Ifthe pressure is within the allowed range (noted above),check the voltage ratio of the transducer. To obtainthe voltage ratio, divide the voltage (d.c.) input fromthe transducer by the TRANSDUCER VOLTAGEREF supply voltage signal (displayed in CONTROLTEST menu in the PRESSURE TRANSDUCERSscreen) or measure across the positive (+ red) andnegative (– black) leads of the transducer. For example,the condenser transducer voltage reference is measuredat CCM terminals J-4 and J-6, the condenser trans-ducer voltage input. The input to reference voltageratio must be between 0.80 and 0.11 for the software toallow calibration. Pressurise the transducer until theratio is within range. Then attempt calibration again.4. A high pressure point can also be calibrated between17.4 and 173.7 kPa by attaching a regulated 174 kPapressure (usually from a nitrogen cylinder). The highpressure point can be calibrated by accessing theappropriate transducer parameter on the HEAT_EXscreen, highlighting the parameter, pressing theSeLeCt softkey, and then using the InCReASe orDeCReASe softkeys to adjust the value to the exactpressure on the refrigerant gauge. Press the enteRsoftkey to finish the calibration. Pressures at highaltitude locations must be compensated for, so thechiller temperature/pressure relationship is correct.The PIC III does not allow calibration if the transducer istoo far out of calibration. In this case, a new transducermust be installed and re-calibrated. If calibration problemsare encountered on the OIL PRESSURE DELTA Pchannel, sometimes swapping the compressor oil dischargepressure transducer and the oil sump pressure transducerwill offset an adverse transducer tolerance stack up andallow the calibration to proceed.