Carrier 19XR User 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

76TROUBLESHOOTING GUIDEOverview — The PIC II has many features to help the op-erator and technician troubleshoot a 19XR chiller.• The CVC/ICVC shows the chiller’s actual operating con-ditions and can be viewed while the unit is running.• The CVC/ICVC default screen freezes when an alarmoccurs. The freeze enables the operator to view thechiller conditions at the time of alarm. The STATUSscreens continue to show current information. Once allalarms have been cleared (by correcting the problemsand pressing the softkey), the CVC/ICVCdefault screen returns to normal operation.• The CONTROL ALGORITHM STATUS screens (whichinclude the CAPACITY, OVERRIDE, LL_MAINT,ISM_HIST, LOADSHED, WSMDEFME, andOCCDEFCM screens) display information that helps todiagnose problems with chilled water temperaturecontrol, chilled water temperature control overrides, hotgas bypass, surge algorithm status, and time scheduleoperation.• The control test feature facilitates the proper operationand test of temperature sensors, pressure transducers, theguide vane actuator, oil pump, water pumps, tower con-trol, and other on/off outputs while the compressor isstopped. It also has the ability to lock off the compressorand turn on water pumps for pumpout operation. TheCVC/ICVC shows the temperatures and pressuresrequired during these operations.• From other SERVICE tables, the operator/technician canaccess configured items, such as chilled water resets,override set points, etc.• If an operating fault is detected, an alarm message is gen-erated and displayed on the CVC/ICVC default screen.A more detailed message — along with a diagnosticmessage — is also stored into the ALARM HISTORYtable.Checking Display Messages — The first area tocheck when troubleshooting the 19XR is the CVC/ICVC dis-play. If the alarm light is flashing, check the primary and sec-ondary message lines on the CVC/ICVC default screen(Fig. 14). These messages will indicate where the fault is oc-curring. These messages contain the alarm message with aspecified code. This code or state appears with each alarm andalert message. The ALARM HISTORY table on the CVC/ICVC SERVICE menu also contains an alarm message to fur-ther expand on the alarm. For a complete list of possible alarmmessages, see Table 11. If the alarm light starts to flash whileaccessing a menu screen, press the softkey to return tothe default screen to read the alarm message. The STATUSscreen can also be accessed to determine where an alarm exists.Checking Temperature Sensors — All temperaturesensors are thermistor-type sensors. This means that the resis-tance of the sensor varies with temperature. All sensors havethe same resistance characteristics. If the controls are on, deter-mine sensor temperature by measuring voltage drop; if the con-trols are powered off, determine sensor temperature by measur-ing resistance. Compare the readings to the values listed inTable 12A or 12B.RESISTANCE CHECK — Turn off the control power and,from the module, disconnect the terminal plug of the sensor inquestion. With a digital ohmmeter, measure sensor resistancebetween receptacles as designated by the wiring diagram. Theresistance and corresponding temperature are listed inTable 12A or 12B. Check the resistance of both wires toground. This resistance should be infinite.VOLTAGE DROP — The voltage drop across any energizedsensor can be measured with a digital voltmeter while the con-trol is energized. Table 12A or 12B lists the relationship be-tween temperature and sensor voltage drop (volts dc measuredacross the energized sensor). Exercise care when measuringvoltage to prevent damage to the sensor leads, connector plugs,and modules. Sensors should also be checked at the sensorplugs. Check the sensor wire at the sensor for 5 vdc if the con-trol is powered on.CHECK SENSOR ACCURACY — Place the sensor in amedium of known temperature and compare that temperatureto the measured reading. The thermometer used to determinethe temperature of the medium should be of laboratory qualitywith 0.5° F (.25° C) graduations. The sensor in question shouldbe accurate to within 2° F (1.2° C).See Fig. 9 for sensor locations. The sensors are immerseddirectly in the refrigerant or water circuits. The wiring at eachsensor is easily disconnected by unlatching the connector.These connectors allow only one-way connection to the sensor.When installing a new sensor, apply a pipe sealant or threadsealant to the sensor threads.DUAL TEMPERATURE SENSORS — For servicing con-venience, there are 2 sensors each on the bearing and motortemperature sensors. If one of the sensors is damaged, the othercan be used by simply moving a wire. The number 2 terminalin the sensor terminal box is the common line. To use the sec-ond sensor, move the wire from the number 1 position to thenumber 3 position.Checking Pressure TransducersUNITS EQUIPPED WITH CVC — There are 8 pressuretransducers on 19XR chillers. They determine cooler, condens-er, oil pressure, and cooler and condenser flow. The cooler andcondenser transducers are also used by the PIC II to determinethe refrigerant temperatures. The oil supply pressure transducervalue and the oil transmission sump pressure transducer valuedifference is calculated by the CCM. The CVC module thendisplays the differential pressure. In effect, the CVC reads onlyone input for oil pressure for a total of 5 pressure inputs: coolerpressure, condenser pressure, oil differential pressure, coolerwaterside differential pressure, and condenser waterside differ-ential pressure. See the Check Pressure Transducers section(page 75) under Scheduled Maintenance.UNITS EQUIPPED WITH ICVC — There are 6 factory-installed pressure transducers, with inputs available for bothcooler and The ICVC software will display a default reading of26 psi during start-up and operation. An additional transducer,factory installed in the bottom of the cooler barrel, will read asEVAPORATOR SACTURATION TEMP on the HEAT_EXDISPLAY screen. This provides additional protection against aloss of water flow condition.These pressure transducers can be calibrated if necessary. Itis not usually necessary to calibrate at initial start-up.However, at high altitude locations, it is necessary to calibratethe transducers to ensure the proper refrigerant temperature/pressure relationship. Each transducer is supplied with 5 vdcpower from the CCM. If the power supply fails, a transducervoltage reference alarm occurs. If the transducer reading issuspected of being faulty, check the supply voltage. It shouldbe 5 vdc ±.5 v displayed in CONTROL TEST under CCMPressure Transducers. If the supply voltage is correct, the trans-ducer should be recalibrated or replaced.RESETEXITRelieve all refrigerant pressure or drain the water beforereplacing the temperature sensors.