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

28Chiller DehydrationDehydration is recommended if the chiller has been open for aconsiderable period of time, if the chiller is known to containmoisture, or if there has been a complete loss of chiller holdingcharge or refrigerant pressure.Dehydration can be done at room temperatures. Using a cold trap(Fig. 27) may substantially reduce the time required to completethe dehydration. The higher the room temperature, the faster dehy-dration takes place. At low room temperatures, a very deep vacu-um is required to boil off any moisture. If low ambient tempera-tures are involved, contact a qualified service representative forthe dehydration techniques required.Fig. 27 — Dehydration Cold TrapPerform dehydration as follows:1. Connect a high capacity vacuum pump (5 cfm [.002 m3/s]or larger is recommended) to the refrigerant chargingvalve (Fig. 3-5). Tubing from the pump to the chillershould be as short in length and as large in diameter aspossible to provide least resistance to gas flow.2. Use an absolute pressure manometer or a digital vacuumgage to measure the vacuum.3. If the entire chiller is to be dehydrated, open all isolationvalves (if present).4. With the chiller ambient temperature at 60°F (15.6°C) orhigher, operate the vacuum pump until the manometerreads 185 psig (1275 kPa), or a vacuum indicator reads35°F (1.7°C). Operate the pump an additional 2 hours.Do not apply a vacuum greater than 29.82 in. Hg vac (757.4mm Hg) or go below 33°F (0.56°C) on the wet bulb vacuumindicator. At this temperature and pressure, isolated pocketsof moisture can turn into ice. The slow rate of evaporation(sublimation) of ice at these low temperatures and pressuresgreatly increases dehydration time.5. Valve off the vacuum pump, stop the pump, and record theinstrument reading.6. After a 2-hour wait, take another instrument reading. If thereading has not changed, dehydration is complete. If thereading indicates vacuum loss, repeat Steps 4 and 5.7. If the reading continues to change after several attempts,perform a leak test up to the maximum 160 psig (1103 kPa)pressure. Locate and repair the leak, and repeat dehydration.8. Once dehydration is complete, the evacuation process cancontinue. The final vacuum prior to charging the unit withrefrigerant should in all cases be 29.9 in. Hg (500 microns,0.07 kPa [abs]) or less.Inspect Water PipingRefer to piping diagrams provided in the certified drawings andthe piping instructions in the 19XR Installation Instructions manu-al. Inspect the piping to the cooler and condenser. Be sure that theflow directions are correct and that all piping specifications havebeen met.Piping systems must be properly vented with no stress on water-box nozzles and covers. Water flows through the cooler and con-denser must meet job requirements. Measure the pressure dropacross the cooler and the condenser.Check Relief ValvesBe sure the relief valves have been piped to the outdoors in com-pliance with the latest edition of ANSI/ASHRAE Standard 15 andapplicable local safety codes. Piping connections must allow foraccess to the valve mechanism for periodic inspection and leaktesting.The standard 19XR relief valves are set to relieve at 185 psig(1275 kPa) chiller design pressure.Check the Optional Pumpout Compressor WaterPipingIf the optional pumpout storage tank and/or pumpout system areinstalled, check to ensure the pumpout condenser water has beenpiped in. Check for field-supplied shutoff valves and controls asspecified in the job data. Check for refrigerant leaks on field-in-stalled piping.Identify and Check Starter/VFDVerify that the starter/VFD in submittal paperwork matches theactual starter/VFD on the jobsite. Typical design characteristic isfor the stater/VFD to be able to operate in the following environ-ment conditions. In all cases identify the starter by reviewingmarking/part number on the inside/outside of the starter cabinetdoors. See Table 8.Locate the appropriate wiring diagrams associated with the identi-fied starter.CAUTIONDo not start or megohm-test the compressor motor or oil pumpmotor, even for a rotation check, if the chiller is under dehy-dration vacuum. Insulation breakdown and severe damagemay result if voltage is applied to the motor.WARNINGStarters must be disconnected by an isolation switch beforeplacing the machine under a vacuum. To be safe, isolate anystarter before evacuating the chiller if you are not sure if thereare live leads to the hermetic motor.CAUTIONWater must be within design limits, clean, and treated to en-sure proper chiller performance and to reduce the potential oftube damage due to corrosion, scaling, or erosion. Carrier as-sumes no responsibility for chiller damage resulting from un-treated or improperly treated water.Table 8 — Starter/VFD IdentificationCONDITION SPECIFICATIONAMBIENT TEMPERATURE(OUTSIDE NEMA 1 ENCLOSURE) 32 to 122°F (0 to 50°C)STORAGE TEMPERATURE(AMBIENT) –40 to 149°F (–40 to 65°C)HUMIDITY 5% to 95%(non-condensing)WARNINGBE AWARE that certain automatic start arrangements can en-gage the starter/VFD. Open the disconnect ahead of the starter/VFD in addition to shutting off the chiller or pump. Failure todo so could result in serious personal injury of death fro elec-tric shock.