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

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Carrier 19XRV Start-up, Operation And Maintenance Instructions Manual Manual pdf 66 page image

CHILLEREQUALIZATIONWITHOUTA PUMPOUTUNITWhenequ_flizingrefrigerantpressureonthe19XRVchillerafterserviceworkorduringtheinitialchillerstall-up,donot use the dischalig, e isolation valve to equali',.e. Eiflier themotor cooling isolation valve or a charging hose (con-nected between the refrigerant charging valves on top ofthe cooler and condenser) should be used as the equaliza-tion valve. Dmnage to the float valve could result.To equalize the pressure differential on a refrigerant isolated19XRV chillek use the terminate lockout function of theCONTROL TEST on the SERVICE menu. This helps to turnon pumps and advises the operator on proper procedures.The following steps describe how to equalize refrigerantpressure in tin isolated 19XRV chiller without a pumpout unit.1. Access terminate lockout function on the CONTROLTEST screen.2. IMPORTANT: Turn on the chilled water and con-[denser water pumps to prevent freezing. I3. Slowly open the motor cooling isolation valve. Thechiller cooler and condenser pressures will graduallyequalize. This process takes approximately 15 minutes.4. Once the pressures have equalized, the cooler isolationv_dve, the condenser isolation valve, and the hot gas isola-tion valve may now be opened. Refer to Fig. 30 and 31,for the location of the valves.Whenever turning the discharge isolation valve, be sine toreattach the valve locking device. This prevents the valvefrom opening or closing during service work or duringchiller operation, which could result in serious pel.sonalinjury.CHILLER EQUALIZATION WITH PUMPOUT UNIT --The following steps describe how to equalize refrigerantpressure on an isolated 19XRV chiller using the pumpout unit.1. Access the terminate lockout function on the CONTROLTEST screen.2. IMPORTANT: Turn on the chilled water and con-]denser water pumps to prevent freezing. I3. Open valve 4 on the pumpout unit and open valves la andl b on the chiller cooler and condensek Fig. 30 and 31.Slowly open valve 2 on the pumpout unit to equalize thepressure. This process takes approximately 15 minutes.4. Once the pressures have equalized, the dischmge isola-tion valve, cooler isolation valve, optional hot gas bypassisolation valve, and the refrigerant isolation valve can beopened. Close valves la and lb, and all pumpout unitvalves.The full refrigerant chmge on the 19XRV will vary withchiller components and design conditions, as indicated on thejob data specifications. An approximate chtuge may be deter-mined by adding the condenser charge to the cooler chmge aslisted in Table 14.Always operate the condenser and chilled water pumpswhenever charging, transferring, or removing refrigerantfrom the chillel: Ftdlure to do so could result in seriouspersonal injury or equipment &image.Use the CONTROL TEST terminate lockout function tomonitor conditions and start the pumps.If the chiller has been shipped with a holding chmge, therefrigerant is added through the pumpout charging connection(Fig. 30 and 31, valve lb). First evacuate the nitrogen holdingchmge from file chiller vessels. Charge the refrigerant as a gasuntil the system pressure exceeds 35 psig (141 kPa) forHFC-134a. Aller the chiller is beyond this pressure the refrig-erant should be charged as a liquid until all the recommendedrefrigerant charge has been added. The charging valve (Fig. 30and 31, v_flve I a or I b) can be used to charge liquid to the cool-er or condenser Do not charge liquid through the liquid lineservice valve.TRIMMING REFRIGERANT CHARGE -- The 19XRV unitis shipped with the correct charge for the design duty of thechillel: On most 19XRV chillers the design LTD (LeavingTemperature Difference) between the leaving chilled watertemperature and the cooler refrigerant temperature is so lowthat the traditional method of trimming the charge to achieve aminimum LTD is not practical. In the case where leaks havebeen found and corrected and the LTD is greater than about4 ° F (2.2 ° C) above design, add refligemnt until the full loaddesign LTD is approached, and then charge for proper oilreturn at low load. (A high cooler LTD can also be caused bydirty tubes, water box division plate bypass, a Du-tiafly closedliquid isolation valve, or a sticking float valve.)If low load oil loss is experienced, operate the chiller at lowload with the guide vanes nedy closed and observe the flowthrough the sight glass in the oil skimmer line. Under low loadoperation one should be able to see a flow of bubbly oil andrefrigerant in the sight glass. If there is no visible flow, addrefrigerant. If the sight glass shows a flow of nearly clear fluid,remove refrigerant.The preferred location at which refrigerant should be addeddirectly into the chiller is through file service valve at the top ofthe condensel: If that valve is not accessible due to presence ofan attached pumpdown unit which does not have a storagetank, add charge through the valve connected to the side of thecondenser drain float sump. Adding charge through the di'ainvalve at the base of the chiller (off file liquid line) is NOTrecommended.Table 14 lists file 19XRV chiller refrigerant charges for eachcooler and condenser code. Total refrigerant charge is the sumof the cooler and condenser charge.66