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

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

Contents

53TROUBLESHOOTING GUIDEOverviewThe PIC 6 control system has many features to help the operatorand technician troubleshoot a 19XR chiller.• The HMI shows the chiller’s actual operating conditionsand can be viewed while the unit is running.• The HMI default screen indicates when an alarm occurs.Once all alarms have been cleared (by correcting the prob-lems), the HMI default screen indicates normal operation.For information about displaying and resetting alarms anda list of alert codes, see the 19XR with PIC 6 Controls Op-eration and Troubleshooting manual.• The Configuration menu screens display information thathelps to diagnose problems with chilled water temperaturecontrol, chilled water temperature control overrides, hotgas bypass, surge algorithm status, and time schedule oper-ation.• The quick test feature facilitates the proper operation andtest of temperature sensors, pressure transducers, the guidevane actuator, diffuser actuator (if equipped), oil pump,water pumps, tower control, and other on/off outputs whilethe compressor is stopped. It also has the ability to lock offthe compressor and turn on water pumps for pumpout op-eration. The HMI shows the temperatures and pressures re-quired during these operations.• If an operating fault is detected, an alarm indicator is dis-played on the HMI default screen. A more detailed mes-sage — along with a diagnostic message — is also storedin the Current Alarms table.• Review the Alarms History table to view other less criticalevents which may have occurred. Compare timing of rele-vant events and alarms.For detailed information about alarms, see the 19XR with PIC 6Controls Operation and Troubleshooting manual. Press the bellicon in the top right corner of the home screen to access currentalarms and alarm history, and to reset alarms.Checking Display MessagesThe first area to check when troubleshooting the 19XR is the HMIdisplay. Status messages are displayed at the bottom of the screen,and the alarm icon indicates a fault. For a complete list of alarms,see the 19XR with PIC 6 Controls Operation and Troubleshootingmanual.Checking Temperature SensorsAll temperature sensors are thermistor-type sensors. This meansthat the resistance of the sensor varies with temperature. All sen-sors have the same resistance characteristics. If the controls are on,determine sensor temperature by measuring voltage drop; if thecontrols are powered off, determine sensor temperature by mea-suring resistance. Compare the readings to the values listed in Ta-bles 12 and 13. The water temperature sensors can be calibrated toa value of 2.0°F (1.2°C).RESISTANCE CHECKTurn off the control power and, from the module, disconnect theterminal plug of the sensor in question. With a digital ohmmeter,measure sensor resistance between receptacles as designated bythe wiring diagram. The resistance and corresponding temperatureare listed in Tables 12 and 13. Check the resistance of both wiresto ground. This resistance should be infinite.VOLTAGE DROPThe voltage drop across any energized sensor can be measuredwith a digital voltmeter while the control is energized. Tables 12and 13 list the relationship between temperature and sensor volt-age drop (volts dc measured across the energized sensor). Exercisecare when measuring voltage to prevent damage to the sensorleads, connector plugs, and modules. Sensors should also bechecked at the sensor plugs.CAUTIONRelieve all refrigerant pressure or drain the water before re-moving any thermowell threaded into the refrigerant pressureboundary. Failure to do so could result in personal injury andequipment damage.