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

Carrier AquaEdge 19XR series Start-up, Operation And Maintenance Instructions Manual Manual pdf 99 page image

99TROUBLESHOOTING GUIDEOverview — The PIC II has many features to help the op-erator and technician troubleshoot a 19XR chiller.• The ICVC shows the chiller’s actual operating condi-tions and can be viewed while the unit is running.• The ICVC default screen freezes when an alarm occurs.The freeze enables the operator to view the chiller condi-tions at the time of alarm. The STATUS screens continueto show current information. Once all alarms have beencleared (by correcting the problems and pressingthe softkey), the ICVC default screen returns tonormal operation.• The CONTROL ALGORITHM STATUS screens (whichinclude the CAPACITY, OVERRIDE, SURGPREV,LL_MAINT, ISM_HIST, LOADSHED, CUR_ALARM,WSMDEFME, and OCCDEFCM screens) display infor-mation that helps to diagnose problems with chilledwater temperature control, chilled water temperaturecontrol overrides, hot gas bypass, surge algorithm status,and time schedule operation.• The control test feature facilitates the proper operationand test of temperature sensors, pressure transducers, theguide vane actuator, diffuser actuator (if equipped), oilpump, water pumps, tower control, and other on/off out-puts while the compressor is stopped. It also has the abil-ity to lock off the compressor and turn on water pumpsfor pumpout operation. The ICVC shows the tempera-tures and pressures required 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 ICVC default screen. A moredetailed message — along with a diagnostic message —is also stored into the ALARM HISTORY table.• Review the ALERT HISTORY table to view other lesscritical events which may have occurred. Compare tim-ing of relevant events and alarms.Checking Display Messages — The first area tocheck when troubleshooting the 19XR is the ICVC display. Ifthe alarm light is flashing, check the chiller primary and sec-ondary message lines on the ICVC default screen (Fig. 17).These messages will indicate where the fault is occurring.These messages contain the alarm message with a specifiedcode. This code or state appears with each alarm and alert mes-sage. The ALARM and ALERT HISTORY tables on the ICVCSERVICE menu also contain an alarm or alert message to fur-ther expand on the alarm or alert. For a complete list of possi-ble alarm messages, see Table 16. If the alarm light starts toflash while accessing a menu screen, press the softkey toreturn to the default screen to read the alarm message. TheSTATUS screen can also be accessed to determine where analarm exists.A “C” to the right of a parameter’s value means that there isa communications fault on that channel.Checking Temperature Sensors — All tempera-ture sensors are thermistor-type sensors. This means that the re-sistance 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 inTables 17A and 17B.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 inTables 17A and 17B. 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 17A or 17B 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.RESETCAUTIONRelieve all refrigerant pressure or drain the water beforeremoving any thermowell threaded into the refrigerantpressure boundary. Failure to do so could result in personalinjury and equipment damage.EXITcontinued on page 116.