Carrier 19XR User Manual

Also see for AquaEdge 19XRV series: Start-up, operation and maintenance instructions Start-up and service instructions Installation instructions Start-up, operation and maintenance instructions Start-up and service instructions

Contents

67Leave the oil charge in the chiller with the oil heater andcontrols energized to maintain the minimum oil reservoirtemperature.After Extended Shutdown — Ensure the water sys-tem drains are closed. It may be advisable to flush the watercircuits to remove any soft rust which may have formed. Thisis a good time to brush the tubes and inspect the Schrader fit-tings on the waterside flow devices for fouling, if necessary.Check the cooler pressure on the CVC/ICVC default screenand compare it to the original holding charge that was left inthe chiller. If (after adjusting for ambient temperature changes)any loss in pressure is indicated, check for refrigerant leaks.See Check Chiller Tightness section, page 48.Recharge the chiller by transferring refrigerant from thepumpout storage tank (if supplied). Follow the Pumpout andRefrigerant Transfer Procedures section, below. Observefreeze-up precautions.Carefully make all regular preliminary and running systemchecks. Perform a Control Test before start-up. If the compres-sor oil level appears abnormally high, the oil may haveabsorbed refrigerant. Ensure that the oil temperature is above140 F (60 C) or above the cooler refrigerant temperature plus50° F (27° C).Cold Weather Operation — When the entering con-denser water temperature drops very low, the operator shouldautomatically cycle the cooling tower fans off to keep the tem-perature up. Piping may also be arranged to bypass the coolingtower. The PIC II controls have a low limit tower fan outputthat can be used to assist in this control (terminal 11 and 12 onISM).Manual Guide Vane Operation — It is possible tomanually operate the guide vanes in order to check controloperation or to control the guide vanes in an emergency. Manu-al operation is possible by overriding the target guide vaneposition. Access the COMPRESS screen on the CVC/ICVCand scroll down to highlight TARGET GUIDE VANE POS. Tocontrol the position, use the orsoftkey to adjust to the percentage of guide vane opening that isdesired. Zero percent is fully closed; 100% is fully open. Torelease the guide vanes to automatic control, press thesoftkey.NOTE: Manual control overrides the configured pulldown rateduring start-up and permits the guide vanes to open at a fasterrate. Motor current above the electrical demand setting, capac-ity overrides, and chilled water temperature below the controlpoint override the manual target and close the guide vanes. Fordescriptions of capacity overrides and set points, see the Con-trols section.Refrigeration Log — A refrigeration log (as shown inFig. 34), is a convenient checklist for routine inspection andmaintenance and provides a continuous record of chiller per-formance. It is also an aid when scheduling routine mainte-nance and diagnosing chiller problems.Keep a record of the chiller pressures, temperatures, and liquidlevels on a sheet similar to the one in Fig. 34. Automaticrecording of PIC II data is possible by using CCN devices suchas the Data Collection module and a Building Supervisor.Contact a Carrier representative for more information.PUMPOUT AND REFRIGERANTTRANSFER PROCEDURESPreparation — The 19XR may come equipped with anoptional pumpout storage tank, pumpout system, or pumpoutcompressor. The refrigerant can be pumped for service work toeither the chiller compressor vessel or chiller condenser vesselby using the optional pumpout system. If a pumpout storagetank is supplied, the refrigerant can be isolated in the storagetank. The following procedures describe how to transfer refrig-erant from vessel to vessel and perform chiller evacuations.Operating the Optional Pumpout Unit1. Be sure that the suction and the discharge service valveson the optional pumpout compressor are open (back-seated) during operation. Rotate the valve stem fullycounterclockwise to open. Front-seating the valve closesthe refrigerant line and opens the gage port to compressorpressure.2. Ensure that the compressor hold-down bolts have beenloosened to allow free spring travel.3. Open the refrigerant inlet valve on the pumpoutcompressor.4. Oil should be visible in the pumpout unit compressorsight glass under all operating conditions and duringshutdown. If oil is low, add oil as described underOptional Pumpout System Maintenance section, page 75.The pumpout unit control wiring schematic is detailed inFig. 35.TO READ REFRIGERANT PRESSURES during pumpout orleak testing:1. The CVC/ICVC display on the chiller control panel issuitable for determining refrigerant-side pressures andlow (soft) vacuum. To assure the desired range and accu-racy when measuring evacuation and dehydration, use aquality vacuum indicator or manometer. This can beplaced on the Schrader connections on each vessel (Fig.9) by removing the pressure transducer.2. To determine pumpout storage tank pressure, a 30 in.-0-400 psi (-101-0-2769 kPa) gage is attached to the stor-age tank.3. Refer to Fig. 29, 30, and 36 for valve locations andnumbers.INCREASE DECREASERELEASEAlways run the chiller cooler and condenser water pumpsand always charge or transfer refrigerant as a gas when thechiller pressure is less than 30 psig (207 kPa). Below thesepressures, liquid refrigerant flashes into gas, resulting inextremely low temperatures in the cooler/condenser tubesand possibly causing tube freeze-up.During transfer of refrigerant into and out of the optionalstorage tank, carefully monitor the storage tank level gage.Do not fill the tank more than 90% of capacity to allow forrefrigerant expansion. Overfilling may result in damage tothe tank or personal injury.Do not mix refrigerants from chillers that use differentcompressor oils. Compressor damage can result.Transfer, addition, or removal of refrigerant in spring-isolated chillers may place severe stress on external pipingif springs have not been blocked in both up and downdirections.