Carrier AQUASNAP AIR COOLED CHILLERS WITH COMFORTLINK CONTROLS 30RAP010-060 Operation And Service Manual

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Carrier AQUASNAP AIR COOLED CHILLERS WITH COMFORTLINK CONTROLS 30RAP010-060 Operation And Service Manual Manual pdf 49 page image

49b. Place a digital voltmeter, on 20-volt AC scale,across the black and white terminals on the con-troller. Restore power to the controller. For at least7 seconds, the voltmeter should read approxi-mately 12 to 14 volts. Significant differences meanthe controller is defective or not properly config-ured for the EXV valve.c. Repeat the procedure in Step b above using the redand green terminals on the controller. If the con-troller responds properly, then the wiring may bedamaged or the valve may be plugged with debrisor otherwise obstructed.d. The EXV valves on sizes 025, 030, 050-060 maybe disassembled for cleaning, inspection or motorassembly replacement.VALVE REPLACEMENT — The valve may be replaced byunsoldering or cutting the piping. A tubing cutter must be usedto prevent creating contaminants in the piping.VALVE REASSEMBLY — Perform the following procedureto reassemble the EXV valve:1. Use Service Test to open the EXV to 100%. This will re-tract the white polyester driver/piston fully into the driverguide. Remove power from the valve or controller.2. Lightly oil the threads, and gasket or knife-edge on thenew motor adaptor. Carefully seat the adaptor on thevalve body or engage and tighten the lock nut if used.Lock nuts should be torqued to approximately 45 ft-lb.One eighth turn more than hand tight is sufficient toachieve a leak proof seal on knife-edge joints.3. After the motor is tightened, the cable should be replacedon the valve. Care should be taken to ensure engagementof the alignment key. Snap on the cable retainer.4. Pressurize the system and check for leaks.5. Reapply power to the ComfortLink™ controller. Since,during service, valve position as calculated by the con-troller will be lost, the controller should be initialized atleast twice. In some instances, cycling power to the con-troller will accomplish this.Compressor Replacement (Refer to Fig. 26and 27) — All models contain scroll compressors and havefrom one to four compressors. The size 010-030 units are a sin-gle refrigeration circuit while sizes 035-060 are dual circuit. Acompressor is most easily removed from the front of the unit,depending on where clearance space was allowed during unitinstallation.Remove the junction box cover bolts and disconnect thecompressor power and ground connections. Remove the cablefrom the compressor junction box. Remove the connectionsfrom the high-pressure switch. Knock the same holes out of thenew compressor junction box and install the cable connectorsfrom the old compressor.The compressors are bolted to rails, which are in turn boltedto the unit basepan for all sizes except 010 and 015 which aredirectly bolted to the basepan. Remove the 4 bolts holding thecompressor to the rail on the basepan. Save the mounting hard-ware for use with the new compressor. Carefully cut the com-pressor suction and discharge lines with a tubing cutter as closeto the compressor as feasible. Remove high-pressure switchand pressure transducer(s) if required for compressor removal.Lift one corner of the compressor at a time and remove all therubber mounting grommets (single compressor circuits) orsteel spacers (dual compressor circuits). Remove the old com-pressor from the unit.Slide the new compressor in place on the basepan. Liftingone side of the compressor at a time, replace all of the compres-sor mounting grommets. Using new tubing as required, recon-nect compressor suction and discharge lines. Using hardwaresaved, reinstall the mounting bolts and washers through thecompressor feet. Using proper techniques, braze suction anddischarge lines and check for leaks. Reconnect oil equalizationline on dual compressor circuit models.Reconnect the compressor power connections and high-pressure switch wiring as on the old compressor. Refer toFig. 26 and 27. Following the installation of the new compres-sor, tighten all hardware to the following specifications. (SeeTable 31.)Table 31 — Unit Torque SpecificationCoolerBRAZED-PLATE COOLER HEAT EXCHANGER RE-PLACEMENT — Brazed-plate heat exchangers cannot berepaired if they develop a leak. If a leak (refrigerant or water)develops, the heat exchanger must be replaced. To replace abrazed-plate heat exchanger:1. Check that the replacement heat exchanger is the same asthe original heat exchanger. The unit insulation covers themanufacturer’s part number. Make sure the depths of thereplacement and original cooler heat exchangers are thesame.BLKWHTGRNREDBLKWHTGRNREDFig. 25 — EXV Cable Connections to EXV Modulea30-4972CAUTIONIf the existing motor has been removed for inspection orcleaning, be sure that the piston is fully retracted into themotor assembly before installation on the valve. Failure todo so will permanently damage the drive and motor.Replacement motor assemblies are shipped in the retractedposition and may be installed as received.FASTENER RECOMMENDED TORQUECompressor MountingBolts 7 to 10 ft-lb (9.5 to 13.5 N-m)Compressor PowerConnections24 to 28 in.-lb (2.7- to 3.2 N-m)Compressor GroundTerminal Connections 14 to 18 in.-lb (1.6 to 2.0 N-m)