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

46GENERAL MAINTENANCERefrigerant PropertiesThe standard refrigerants for the 19XR chiller are HFC-134a/R-513A. At normal atmospheric pressure, HFC-134a/R-513Awill boil at –14°F (–25°C)/ –28°F (–33°C) and must, therefore, bekept in pressurized containers or storage tanks. The refrigerant ispractically odorless when mixed with air and is noncombustible atatmospheric pressure. Read the Material Safety Data Sheet and thelatest ASHRAE Safety Guide for Mechanical Refrigeration tolearn more about safe handling of this refrigerant.Adding RefrigerantFollow the procedures described in Trim Refrigerant Charge sec-tion, page 48.Adjusting the Refrigerant ChargeIf the addition or removal of refrigerant is required to improvechiller performance, follow the procedures given under the TrimRefrigerant Charge section, page 48.Refrigerant Leak TestingBecause HFC-134a is above atmospheric pressure at room tem-perature, leak testing can be performed with refrigerant in thechiller. Use an electronic halogen leak detector, soap bubble solu-tion, or ultrasonic leak detector. Ensure that the room is well venti-lated and free from concentration of refrigerant to keep false read-ings to a minimum. Before making any necessary repairs to a leak,transfer all refrigerant from the leaking vessel.Leak RateIt is recommended by ASHRAE that chillers be taken off line im-mediately and repaired if the refrigerant leak rate for the entirechiller is more than 10% of the operating refrigerant charge peryear.In addition, Carrier recommends that leaks totaling less than theabove rate but more than a rate of 0.1% of the total charge per yearshould be repaired during annual maintenance or whenever the re-frigerant is transferred for other service work.Test After Service, Repair, or Major LeakIf all the refrigerant has been lost or if the chiller has been openedfor service, the chiller or the affected vessels must be pressure test-ed and leak tested. Refer to the Leak Test Chiller section onpage 26 to perform a leak test.TESTING WITH REFRIGERANT TRACERUse an environmentally acceptable refrigerant as a tracer for leaktest procedures. Use dry nitrogen to raise the machine pressure toleak testing levels.TESTING WITHOUT REFRIGERANT TRACERAnother method of leak testing is to pressurize with nitrogen onlyand to use a soap bubble solution or an ultrasonic leak detector todetermine if leaks are present.TO PRESSURIZE WITH DRY NITROGENNOTE: Pressurizing with dry nitrogen for leak testing should notbe done if the full refrigerant charge is in the vessel because purg-ing the nitrogen is very difficult.1. Connect a copper tube from the pressure regulator on thecylinder to the refrigerant charging valve. Never apply fullcylinder pressure to the pressurizing line. Follow the listedsequence.2. Open the charging valve fully.3. Slowly open the cylinder regulating valve.4. Observe the pressure gage on the chiller and close the reg-ulating valve when the pressure reaches test level. Do notexceed 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 ApplyStanding Vacuum TestAfter pressurizing the chiller, test for leaks with an electronic ha-lide leak detector, soap bubble solution, or an ultrasonic leak de-tector. Bring the chiller back to atmospheric pressure, repair anyleaks found, and retest.After retesting and finding no leaks, apply a standing vacuum test.Then dehydrate the chiller. Refer to the Standing Vacuum Test andChiller Dehydration sections (pages 26 and 28) in the Before Ini-tial Start-Up section.Checking Guide VanesDuring normal shutdown, when the chiller is off, the guide vanesare closed. Check that the coupling is tight on the shaft and makesure that the guide vane shaft is closed. Complete the followingsteps to adjust position (see Fig. 46-49):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 suction housing.4. If required, rotate the guide vane sprocket fully clockwiseand spot-drill the guide vane actuator shaft. Spot-drillingis necessary when the guide vane actuator sprocket setscrews on the guide vane actuator shaft need to be re-seated. (Remember: Spot-drill and tighten the first setscrew before spot-drilling for the second set screw.)DANGERHFC-134a/R-513A will dissolve oil and some nonmetallicmaterials, dry the skin, and, in heavy concentrations, may dis-place enough oxygen to cause asphyxiation. When handlingthis refrigerant, protect the hands and eyes and avoid breathingfumes.CAUTIONAlways use the compressor pumpdown function in the PUMP-DOWN/LOCKOUT feature to turn on the cooler pump andlock out the compressor when transferring refrigerant. Liquidrefrigerant may flash into a gas and cause possible freeze-upwhen the chiller pressure is below 35 psig (241 kPa) for HFC-134a or 39 psig (268 kPa) for R-513A.WARNINGHFC-134a/HFO-513A should not be mixed with air or oxy-gen and pressurized for leak testing. In general, this refriger-ant should not be present with high concentrations of air oroxygen above atmospheric pressures, because the mixturecan undergo combustion.