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

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Contents

58Leak Test Chiller — Due to regulations regarding refrig-erant emissions and the difficulties associated with separatingcontaminants from the refrigerant, Carrier recommends thefollowing leak test procedure. See Fig. 29 for an outline of theleak test procedure. Refer to Fig. 30 and 31 during pumpoutprocedures and Tables 11A and 11B for refrigerant pressure/temperature values.1. If the pressure readings are normal for the chillercondition:a. Evacuate the holding charge from the vessels, ifpresent.b. Raise the chiller pressure, if necessary, by addingrefrigerant until pressure is at the equivalent satu-rated pressure for the surrounding temperature.Follow the pumpout procedures in the TransferRefrigerant from Pumpout Storage Tank to Chillersection, Steps 1a - e, page 75.c. Leak test chiller as outlined in Steps 3-9.2. If the pressure readings are abnormal for the chillercondition:a. Prepare to leak test chillers shipped with refriger-ant (Step 2h).b. Check for large leaks by connecting a nitrogen bottleand raising the pressure to 30 psig (207 kPa). Soaptest all joints. If the test pressure holds for 30 minutes,prepare the test for small leaks (Steps 2g-h).c. Plainly mark any leaks that are found.d. Release the pressure in the system.e. Repair all leaks.f. Retest the joints that were repaired.g. After successfully completing the test for largeleaks, remove as much nitrogen, air, and moistureas possible, given the fact that small leaks may bepresent in the system. This can be accomplished byfollowing the dehydration procedure, outlined inthe Chiller Dehydration section, page 61.h. Slowly raise the system pressure to a maximum of160 psig (1103 kPa) but no less than 35 psig(241 kPa) for HFC-134a by adding refrigerant.Proceed with the test for small leaks (Steps 3-9).3. Check the chiller carefully with an electronic leak detec-tor, halide torch, or soap bubble solution.4. Leak Determination — If an electronic leak detectorindicates a leak, use a soap bubble solution, if possible, toconfirm. Total all leak rates for the entire chiller. Leakageat rates greater than 0.1% of the total charge per year mustbe repaired. Note the total chiller leak rate on the start-upreport.5. If no leak is found during the initial start-up procedures,complete the transfer of refrigerant gas from the pumpoutstorage tank to the chiller (see Transfer Refrigerant fromPumpout Storage Tank to Chiller section, page 75).Retest for leaks.6. If no leak is found after a retest:a. Transfer the refrigerant to the pumpout storagetank and perform a standing vacuum test asoutlined in the Standing Vacuum Test section,below.b. If the chiller fails the standing vacuum test, checkfor large leaks (Step 2b).c. If the chiller passes the standing vacuum test,dehydrate the chiller. Follow the procedure inthe Chiller Dehydration section. Charge the chillerwith refrigerant (see Transfer Refrigerant fromPumpout Storage Tank to Chiller section,page 75).7. If a leak is found after a retest, pump the refrigerant backinto the pumpout storage tank or, if isolation valves arepresent, pump the refrigerant into the non-leakingvessel (see Pumpout and Refrigerant Transfer Proceduressection).8. Transfer the refrigerant until the chiller pressure is at18 in. Hg (40 kPa absolute).9. Repair the leak and repeat the procedure, beginning fromStep 2h, to ensure a leak-tight repair. (If the chiller isopened to the atmosphere for an extended period, evacu-ate it before repeating the leak test.)Standing Vacuum Test — When performing the stand-ing vacuum test or chiller dehydration, use a manometer or awet bulb indicator. Dial gages cannot indicate the small amountof acceptable leakage during a short period of time.1. Attach an absolute pressure manometer or wet bulbindicator to the chiller.2. Evacuate the vessel (see Pumpout and RefrigerantTransfer Procedures section, page 74) to at least 18 in. Hgvac, ref 30-in. bar (41 kPa), using a vacuum pump or thepumpout unit.3. Valve off the pump to hold the vacuum and record themanometer or indicator reading.4. a. If the leakage rate is less than 0.05 in. Hg (0.17 kPa) in24 hours, the chiller is sufficiently tight.b. If the leakage rate exceeds 0.05 in. Hg (0.17 kPa) in24 hours, repressurize the vessel and test for leaks.If refrigerant is available in the other vessel, pressur-ize by following Steps 2-10 of Return Chiller ToNormal Operating Conditions section, page 76. Ifnot, use nitrogen and a refrigerant tracer. Raise thevessel pressure in increments until the leak isdetected. If refrigerant is used, the maximum gaspressure is approximately 70 psig (483 kPa) forHFC-134a at normal ambient temperature. If nitro-gen is used, limit the leak test pressure to 160 psig(1103 kPa) maximum.Never charge liquid refrigerant into the chiller if the pres-sure in the chiller is less than 35 psig (241 kPa) forHFC-134a. Charge as a gas only, with the cooler andcondenser pumps running, until this pressure is reached,using PUMPDOWN LOCKOUT and TERMINATELOCKOUT mode on the PIC III. Flashing of liquidrefrigerant at low pressures can cause tube freeze-up andconsiderable damage.