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

Also see for HERMETIC CENTRIFUGAL LIQUID CHILLERS 19XR: User manual Start-up and service instructions Installation instructions Product data Installation instructions

Contents

Carrier 19XR Start-up, Operation And Maintenance Instructions Manual Manual pdf 65 page image

GENERAL MAINTENANCERefrigerant Properties — The standard refrigerant forthe 19XR chiller is HFC-134a. At normal atmospheric pres-sure, HFC-134a will boil at –14 F (–25 C) and must, there-fore, be kept in pressurized containers or storage tanks. Therefrigerant is practically odorless when mixed with airand is noncombustible at atmospheric pressure. Read theMaterial Safety Data Sheet and the latest ASHRAE SafetyGuide for Mechanical Refrigeration to learn more about safehandling of this refrigerant.HFC-134a will dissolve oil and some nonmetallic ma-terials, dry the skin, and, in heavy concentrations, maydisplace enough oxygen to cause asphyxiation. Whenhandling this refrigerant, protect the hands and eyes andavoid breathing fumes.Adding Refrigerant — Follow the procedures de-scribed in Trim Refrigerant Charge section, this page.Always use the compressor pumpdown function in theControl Test table to turn on the cooler pump and lockout the compressor when transferring refrigerant. Liq-uid refrigerant may flash into a gas and cause possiblefreeze-up when the chiller pressure is below30 psig (207 kPa) for HFC-134a.Removing Refrigerant — If the optional pumpout sys-tem is used, the 19XR refrigerant charge may be transferredto a pumpout storage tank or to the chiller condenser or coolervessels. Follow the procedures in the Pumpout and Refrig-erant Transfer Procedures section when transferring refrig-erant from one vessel to another.Adjusting the Refrigerant Charge — If the addi-tion or removal of refrigerant is required to improve chillerperformance, follow the procedures given under the TrimRefrigerant Charge section, this page.Refrigerant Leak Testing — Because HFC-134a isabove atmospheric pressure at room temperature, leak test-ing can be performed with refrigerant in the chiller. Use anelectronic halide leak detector, soap bubble solution, or ultra-sonic leak detector. Ensure that the room is well ventilatedand free from concentration of refrigerant to keep false read-ings to a minimum. Before making any necessary repairs toa leak, transfer all refrigerant from the leaking vessel.Leak Rate — It is recommended byASHRAE that chill-ers be taken off line immediately and repaired if the refrig-erant leak rate for the entire chiller is more than 10% of theoperating refrigerant charge per year.In addition, Carrier recommends that leaks totalling lessthan the above rate but more than a rate of 0.1% of the totalcharge per year should be repaired during annual mainte-nance or whenever the refrigerant is transferred for other serv-ice work.Test After Service, Repair, or Major Leak — Ifall the refrigerant has been lost or if the chiller has been openedfor service, the chiller or the affected vessels must be pres-sure tested and leak tested. Refer to the Leak Test Chillersection to perform a leak test.HFC-134a should not be mixed with air or oxygen andpressurized for leak testing. In general, this refrigerantshould not be present with high concentrations of air oroxygen above atmospheric pressures, because the mix-ture can undergo combustion.REFRIGERANT TRACER — Use an environmentallyacceptable refrigerant as a tracer for leak test procedures.TO PRESSURIZE WITH DRY NITROGEN — Anothermethod of leak testing is to pressurize with nitrogen onlyand to use a soap bubble solution or an ultrasonic leakdetector to determine if leaks are present.NOTE: Pressurizing with dry nitrogen for leak testing shouldonly be done if all refrigerant has been evacuated from thevessel.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. Donot exceed 140 psig (965 kPa).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 bubblesolution, or an ultrasonic leak detector. Bring the chiller backto atmospheric pressure, repair any leaks found, and retest.After retesting and finding no leaks, apply a standing vacuumtest. Then dehydrate the chiller. Refer to the Standing VacuumTest and Chiller Dehydration section (pages 48 and 51) inthe Before Initial Start-Up section.Checking Guide Vane Linkage — When thechiller is off, the guide vanes are closed and the actuatormechanism is in the position shown in Fig. 33. If slack de-velops in the drive chain, do the following to eliminatebacklash:1. With the chiller shut down and the actuator fully closed,remove the chain guard and loosen the actuator bracketholddown bolts.2. Loosen guide vane sprocket adjusting bolts.3. Pry bracket upwards to remove slack, then retighten thebracket holddown bolts.4. Retighten the guide vane sprocket adjusting bolts. En-sure that the guide vane shaft is rotated fully in the clock-wise direction in order close it fully.Trim Refrigerant Charge — If, to obtain optimal chillerperformance, it becomes necessary to adjust the refrigerantcharge, operate the chiller at design load and then add orremove refrigerant slowly until the difference between theleaving chilled water temperature and the cooler refrigeranttemperature reaches design conditions or becomes a mini-mum. Do not overcharge.Refrigerant may be added either through the storage tankor directly into the chiller as described in the ChargeRefrigerant into Chiller section.To remove any excess refrigerant, follow the procedure inTransfer Refrigerant from Chiller to Pumpout Storage Tanksection, Steps 1a and b, page 63.65