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

Carrier AquaEdge 19XR series Start-up, Operation And Maintenance Instructions Manual Manual pdf 14 page image

14During the chiller start-up, the oil pump is energized andprovides 40 seconds of lubrication to the bearings after pres-sure is verified before starting the compressor. During shut-down, the oil pump runs for 60 seconds to ensure lubrication asthe compressor coasts to a stop. The oil pump can also be ener-gized for testing purposes by using the Controls Test.Ramp loading can be adjusted to help to slow the rate ofguide vane opening to minimize oil foaming at start-up. If theguide vanes open quickly, the sudden drop in suction pressurecan cause any refrigerant in the oil to flash. The resulting oilfoam cannot be pumped efficiently; therefore, oil pressure fallsoff and lubrication is poor. If oil pressure falls below 15 psid(103 kPad) differential, the PIC II controls will shut down thecompressor.When the oil pump is not running and the oil heater remainsenergized for 30 minutes, the oil pump will be started and willrun for 30 seconds to evenly distribute the heat in the oilsystem.There are three pump-filter configurations. The originalvane pump, in which the oil filter is contained in the pumphousing, followed by the vane pump with the oil filter beingexternal in the oil piping between the oil pump and the oil cool-er. The third configuration is the gerotor pump, also with theexternal oil filter.A gerotor pump has two rotors, one is inside the other andtheir center points are offset with respect to each other. Thistype of pump provides a smooth continuous flow. It is also qui-eter than other designs.The gerotor pump can be most easily identified by the exter-nal location of the oil pressure regulator. The regulator islocated on the bottom of the pump pointing horizontally to theleft. See Fig. 8.Bearings — The 19XR compressor assemblies includefour radial bearings and four thrust bearings. The low speedshaft assembly is supported by two journal bearings located be-tween the motor rotor and the bull gear. The bearing closer tothe rotor includes a babbitted thrust face which opposes thenormal axial forces which tend to pull the assembly towardsthe transmission. The bearing closer to the bull gear includes asmaller babbitted thrust face, designed to handle counterthrustforces.For compressors equipped with hydrodynamic bearings, thehigh speed shaft assembly is supported by two journal bearingslocated at the transmission end and mid-span, behind the laby-rinth seal. The transmission side of the midspan bearing alsocontains a tilting shoe type thrust bearing which opposes themain axial forces tending to pull the impeller towards the suc-tion end. The impeller side face of the midspan bearing in-cludes a babbitted thrust face, designed to handle counterthrustforces.For compressors equipped with rolling element bearings,the high speed shaft assembly has been redesigned to utilizerolling element bearings (radial and thrust). Machines employ-ing the rolling element bearings can be expected to have higheroil pressure and thrust bearing temperatures than those com-pressors using the alternate bearing design.Oil Reclaim System — The oil reclaim system returnsoil lost from the compressor housing back to the oil reservoirby recovering the oil from 2 areas on the chiller. The guidevane housing is the primary area of recovery. Oil is also recov-ered by skimming it from the operating refrigerant level in thecooler vessel.PRIMARY OIL RECOVERY MODE — Oil is normally re-covered through the guide vane housing on the chiller. This ispossible because oil is normally entrained with refrigerant inthe chiller. As the compressor pulls the refrigerant up from thecooler into the guide vane housing to be compressed, the oilnormally drops out at this point and falls to the bottom of theguide vane housing where it accumulates. Using discharge gaspressure to power an eductor, the oil is drawn from the housingand is discharged into the oil reservoir.1. GERATOR OIL PUMP2. ISOLATION VALVE3. OIL PRESSURE REGULATOR VALVE4. OIL SUMP PRESSURE TRANSDUCER5. OIL SUMP DRAIN6. BEARING TEMPERATURE SENSOR TERMINAL BLOCK7. OIL HEATER2135764Fig. 8 — Gerotor Oil Pump a19-1852