Carrier 17DA Start-up, Operation And Maintenance Instructions Manual

Also see for 17DA: Start-up instructions Application data Operating and maintenance instructions Start-up instructions

132. Open valves 1, 2, 5, 6, 7, and 12.3. Close valves 3, 4, 8, 9, 10 ,11, and 13.4. Operate the pumpout compressor (control switch in theON position).5. When all of the liquid refrigerant has been removed fromthe storage tank, stop the pumpout compressor and closevalves 1, 2, 5, 6, 7, and 12 (all valves closed).6. Open valve 10 and plugged drain connection 14. Drainwater and impurities. Do not allow storage tank pressureto drop below 0 psig.7. Close valve 10 and plugged drain connection 14.8. If, after distilling the refrigerant, there is excess refriger-ant in the cooler over the normal operating charge, thenreturn the excess to the storage tank. Follow the proce-dure Transfer Refrigerant from Machine to Storage Tankon page 12.CHARGE REFRIGERANT — The pumpout unit can aid incharging refrigerant into a dehydrated machine. Perform thefollowing procedure. See Fig. 4 for valve numbers.1. Follow the procedure for Machine and Storage TankEvacuation (No Refrigerant in System) on page 11 to re-move any non-condensable gases, if present.2. Using temporary charging lines, connect the vent of therefrigerant supply cylinder to valve 13 and the cylinderliquid drain to valve 10. Purge the lines as final connec-tion is made to the valves.3. Open valves 2, 4, 5, 6, 7, 10, and 13.4. Close valves 1, 3, 8, 9, 11, and 12.5. Drain any remaining liquid by raising cylinder pressureabove storage tank pressure. Close valve 4 and operatepumpout compressor with control switch in ON position.MAINTENANCEThe primary controls, both operating and safety are now in-corporated into the programmable logic controller (PLC)which is incorporated into the chiller main control panel. Cus-tomer specifications may require some or all of the sensors andsafeties to be duplicated by mechanical switched. For this rea-son both types of sensors and safeties will be covered in the fol-lowing procedures.Weekly MaintenanceCHECK OIL LEVEL — Mark edge of sight glass at normaloil level using grease pencil. Record date and amount of oiladded in refrigeration log.CHECK PURGE FREQUENCY — Operate the purge onlywhen there is air in the system as indicated by the pressure inthe purge chamber when the machine is in operation. Whenpurge chamber pressure is within 8 psid of condenser pressure,the vent valve can be opened to bleed air from the chamber.Close the valve when the differential is higher than 16 psid.WATER IN PURGE WATER CHAMBER — RefrigerantsR-22 and R-134a hold a greater percentage of water in the liq-uid state than in the vapor state. As a result, a typical condens-ing purge does not separate water from refrigerant. Alternatemethods such as refrigerant analysis are used to detect water inthese refrigerants.Yearly MaintenanceNOTE: The primary controls, both operating and safety, arenow incorporated into the PLC, which is incorporated into thechiller main control panel. Customer specifications mayrequire some or all of the sensors and safeties to be duplicatedby mechanical switches. For this reason both types of sensorsand safeties will be covered in the following procedures.CHECK/CALIBRATE WATER TEMPERATURE SEN-SORS — The water temperature sensors are located in the out-let piping near the water nozzles.1. Each sensor should be compared against a calibrated sen-sor in a calibration bath or dry block calibrator.2. Compare the reading of the calibrated sensor with thetemperature reading on the PLC screen. Replace or cali-brate the sensor as required.3. Confirm that any set points on the PLC match the recom-mended alarm or trip points for the chiller.CHECK REFRIGERANT LOW-PRESSURE CUTOUT —The primary low-pressure cutout will be a function of the PLCand the pressure will be transmitted to the PLC from a trans-ducer. An optional mechanical secondary switch may also beinstalled which will send an open-closed signal to the PLC.1. Compare the reading of the cooler pressure transducerwith a test gage and/or the condenser pressure transducerwhen the machine is not in operation. Confirm that thecorrect cutout pressure is configured in the PLC.2. The chilled water low-temperature cutout set point mustbe temporarily set low enough that the refrigerant low-pressure cutout will react first. A mechanical low chillerwater temperature switch should be jumpered for the du-ration of the test.3. Start the machine and observe both chilled water temper-ature and refrigerant temperature.4. Slowly reduce the chilled water temperature controlpoint. Watch the thermometer in the leaving chilled waterline and/or the leaving chilled water temperature displayon the PLC screen. Do not allow chilled water tempera-ture to drop below 35 F.5. The machine should shut down when refrigerant temper-ature reaches one degree below design suction tempera-ture or 28 F (-2.22 C) minimum (chilled water duty).6. Restore the chilled water low-temperature cutout to itsnormal set point. Remove the jumper on the mechanicalchilled water low-temperature cutout switch.CHECK CONDENSER HIGH-PRESSURE CUTOUT —This PLC function and optional mechanical pressure switchsenses condenser gas pressure and shuts down the compressorwhen the condenser pressure exceeds 165 psig (1138 kPa) forR-134a or 275 psig (1896 kPa) for R-22. Do not attempt to testthis safety by forcing the condensing pressure to rise duringmachine operation.1. Compare the reading of the condenser pressure transduc-er with a test gage and/or the cooler pressure transducerwhen the machine is not in operation. Confirm that thecorrect cutout pressure is configured in the PLC.2. To check a mechanical cutout switch, first turn off thecontrol power.3. Use an air or nitrogen supply which can be regulated tothe desired pressure.4. Check the control with an ohmmeter to determine if theswitch has opened when the desired pressure is reached.Adjust as necessary.CHECK AUXILIARY OIL PUMP CONTROL — The pur-pose of the auxiliary oil pump is to take over the job of supply-ing lubricating oil at the required pressure to the bearings andthe seal in the event that the main oil pump loses pressure. Theauxiliary oil pump should start before the machine trips on lowoil pressure. The pressure being measured is the differentialpressure between the machine internal pressure on theValve 1 2 3 4 5 6 7 8 9 10 11 12 13Condition O O C C O O O C C C C O CValve 1 2 3 4 5 6 7 8 9 10 11 12 13Condition C O C O O O O C C O C C O