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

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Carrier AquaEdge 19XR series Start-up, Operation And Maintenance Instructions Manual Manual pdf 88 page image

88the pulldown rate can be decreased to avoid a highdemand charge for the short period of high demand oper-ation. Pulldown rate can be based on load rate or tempera-ture rate and is accessed on the EQUIPMENT SERVICEscreen, RAMP_DEM table (Table 3, Example 23).9. The economizer (if installed) has two sight glasses thatlook into the float chamber. When the chiller is operating,the top sight glass is empty and the bottom sight glass isfull.To Stop the Chiller1. The occupancy schedule starts and stops the chiller auto-matically once the time schedule is configured.2. By pressing the STOP button for one second, the alarmlight blinks once to confirm the button has been pressed.The compressor will then follow the normal shutdownsequence as described in the Shutdown Sequence, Start-Up/Shutdown/Recycle Sequence section, page 64. Thechiller will not restart until the or softkeyis pressed. The chiller is now in the OFF control mode.If the chiller is stopped by an alarm condition, do not re-start the chiller until the problem is diagnosed and cor-rected.After Limited Shutdown — No special preparationsshould be necessary. Follow the regular preliminary checks andstarting procedures.Preparation for Extended Shutdown — The refrig-erant should be transferred into the pumpout storage tank (ifsupplied; see Pumpout and Refrigerant Transfer Procedures) toreduce chiller pressure and the possibility of leaks. Maintain aholding charge of 5 to 10 lb (2.27 to 4.5 kg) of refrigerant or ni-trogen to prevent air from leaking into the chiller.If freezing temperatures are likely to occur in the chiller ar-ea, drain the chilled water, condenser water, and the pumpoutcondenser water circuits to avoid freeze-up. Keep the waterboxdrains open. It is recommended not to store the refrigerant inthe unit if below freezing temperatures are anticipated. A nitro-gen holding charge is recommended in this case.Leave 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 ICVC default screen andcompare it to the original holding charge that was left in thechiller. If (after adjusting for ambient temperature changes) anyloss in pressure is indicated, check for refrigerant leaks. SeeCheck Chiller Tightness section, page 67.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 have ab-sorbed refrigerant. Ensure that the oil temperature is above140 F (60 C) or above the CALC EVAP SAT TEMP plus 50 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 J9-11 and J9-12 on ISM).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 ICVC andscroll down to highlight TARGET GUIDE VANE POS. To con-trol the position, use the or soft-key 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. 46), 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 liq-uid levels on a sheet similar to the one in Fig. 46. 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 chiller may come equippedwith an optional pumpout storage tank, pumpout system, orpumpout compressor. The refrigerant can be pumped for ser-vice work to either the chiller compressor vessel or chiller con-denser vessel by using the optional pumpout system. If apumpout storage tank is supplied, the refrigerant can be iso-lated in the storage tank. The following procedures describehow to transfer refrigerant from vessel to vessel and performchiller evacuation.IMPORTANT: Do not attempt to stop the chiller by openingan isolating knife switch. High intensity arcing may occur.CCN LOCALCAUTIONThe power to the pumpout compressor oil heater must beon whenever any valve connecting the pumpout compres-sor to the chiller or storage tank is open. Leaving the heateroff will result in oil dilution by refrigerant and can lead tocompressor failure.If the compressor is found with the heater off and avalve open the heater must be on for at least 4 hours todrive the refrigerant from the oil. When heating the oil thecompressor suction must be open to a vessel to give the re-frigerant a means to leave the compressor.CAUTIONAlways run the chiller cooler and condenser water pumpsand always charge or transfer refrigerant as a gas when thechiller pressure is less than 35 psig (241 kPa). Below thesepressures, liquid refrigerant flashes into gas, resulting inextremely low temperatures in the cooler/condenser tubesand possibly causing tube freeze-up.INCREASE DECREASERELEASE