Carrier AquaEdge 19DV series Start-up, Operation And Maintenance Instructions Manual

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Carrier AquaEdge 19DV series Start-up, Operation And Maintenance Instructions Manual Manual pdf 41 page image

41GENERAL MAINTENANCERefrigerant Properties — The standard refrigerant forthe 19DV chiller is HFO R-1233zd(E). At normal atmosphericpressure, HFO R-1233zd(E) will boil at 65°F (18°C) and must,therefore, be kept in pressurized containers or storage tanks.The refrigerant is practically odorless when mixed with air andis noncombustible at atmospheric pressure. Read the MaterialSafety Data Sheet and the latest ASHRAE Safety Guide forMechanical Refrigeration to learn more about safe handling ofthis refrigerant.Adding Refrigerant — Follow the procedures de-scribed in Trim Refrigerant Charge section, page 43.Adjusting the Refrigerant Charge — If the addi-tion or removal of refrigerant is required to improve chiller per-formance, follow the procedures given under the Trim Refrig-erant Charge section, page 43.Refrigerant Leak Testing — Since parts of the refrig-erant system operates in vacuum non-condensables will enterthe cooling systems. The PIC5 HMI will issue an alert indicat-ing excessive purge operation. Leaks, which cause frequentpurge cycles, should be repaired without delay. Non-condens-able gas in the machine causes higher than normal condenserpressure, compressor surge at start-up and frequent purge cy-cles, so locate and repair any leaks as soon as possible. Beforemaking any necessary repairs to a leak, transfer all refrigerantfrom the vessel.Leak Rate — It is recommended by ASHRAE that chillersbe taken off line immediately and repaired if the refrigerantleak rate for the entire chiller is more than 10% of the operatingrefrigerant charge per year.Carrier recommends that leaks totaling less than the aboverate but more than a rate of 0.1% of the total charge per yearshould be repaired during annual maintenance or whenever therefrigerant is transferred for other service work.Test After Service, Repair, or Major Leak — If allthe refrigerant has been lost or if the chiller has been opened forservice, the chiller or the affected vessels must be pressure test-ed and leak tested. Refer to the Leak Test Chiller section onpage 18 to perform a leak test.TESTING WITH REFRIGERANT TRACER — Use an en-vironmentally acceptable refrigerant as a tracer for leak testprocedures. Use dry nitrogen to raise the machine pressure toleak testing levels.TESTING WITHOUT REFRIGERANT TRACER — An-other method of leak testing is to pressurize with nitrogen onlyand to use a soap bubble solution or an ultrasonic leak detectorto determine if leaks are present.TO PRESSURIZE WITH DRY NITROGENNOTE: Pressurizing with dry nitrogen for leak testing shouldnot be done if the full refrigerant charge is in the vesselbecause purging the nitrogen is very difficult.1. Connect a copper tube from the pressure regulator on thecylinder to the refrigerant charging valve. Never applyfull cylinder pressure to the pressurizing line. Follow thelisted sequence.2. Open the charging valve fully.3. Slowly open the cylinder regulating valve.4. Observe the pressure gage on the chiller and close theregulating valve when the pressure reaches test level.Do not exceed maximum allowable test pressure 45 psig(310 kPa) for units marked 57 MAWP to allow for plen-ty of margin to avoid from bursting the rupture discs.5. Close the charging valve on the chiller. Remove the cop-per tube if it is no longer required.Repair the Leak, Retest, and Apply StandingVacuum Test — After pressurizing the chiller, test forleaks with an electronic halide leak detector, soap bubble solu-tion, or an ultrasonic leak detector. Bring the chiller back to at-mospheric pressure, repair any leaks found, and retest.After retesting and finding no leaks, apply a standing vacu-um test. Then dehydrate the chiller. Refer to the Standing Vacu-um Test and Chiller Dehydration sections (pages 18 and 20) inthe Before Initial Start-Up section.Checking Guide Vanes — During normal shut-down, when the chiller is off, the guide vanes are closed.Complete the following steps to adjust position if required(see Fig. 39-40):1. Remove the set screw in the guide vane coupling.2. Loosen the holddown bolts on the guide vane actuator.3. Pull the guide vane actuator away from the suctionhousing.DANGERHFO R-1233zd(E) in heavy concentrations may displaceenough oxygen to cause asphyxiation. When handling thisrefrigerant, protect the hands and eyes and avoid breathingfumes.CAUTIONAlways use the compressor pumpdown function in thePUMPDOWN/LOCKOUT feature to turn on the coolerpump and lock out the compressor when transferringrefrigerant. Liquid refrigerant may flash into a gas andcause possible freeze-up when the chiller pressure is below–15 in. Hg (–53 kPa) for HFO R-1233zd(E).WARNINGHFO R-1233zd(E) should not be mixed with air or oxygenand pressurized for leak testing. In general, this refrigerantshould not be present with high concentrations of air oroxygen above atmospheric pressures, because the mixturecan undergo combustion.