Carrier 19XRV Start-up, Operation And Maintenance Instructions Manual

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Carrier 19XRV Start-up, Operation And Maintenance Instructions Manual Manual pdf 69 page image

8. Thecompressormayoperateatfull capacityfora shorttimeafterthepulldownrampinghasended,eventhoughthebuildingloadis sm_dl.Theactiveelectric_ddemandsettingcanbeoveMddentolimitthecompressor[kW.orthepulldownrotecanbedecreasedto avoida highdemandchaisefor theshortperiodof highdemandoperation.Pulldownratecanbebasedonloadrateortemperaturerateandis accessedontheEQUIPMENTSERVICEscreen,RAMPDEM table (N_ble4,Example21).To Stop the ChillerI. The occupancy schedule starts and stops the chillerautomatically 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 50.The chiller will not restmt until the _ orsoftkey is pressed. The chiller is now in the OFF controlmode.l IMPORTANT: Do not attempt to stop the chiller by openingan isolating knife switch. High intensity arcing may occm:Do not restart the chiller until the problem is diagnosedand corrected.After Limited Shutdown-- No speci_d 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 Refiigermlt Transfer Procedures) toreduce chiller pressure and the possibility of leaks. Maintain aholding ch;uge of 5 to 10 lb (2.27 to 4.5 kg) of refrigerant ornitrogen to prevent air from leaking into the chillel:If freezing temperatures ;u'e likely to occur in the chillerarea, drain the chilled watel: condenser watel; and the pumpoutcondenser water circuits to avoid freeze-up. Keep the waterboxdrains open.Leave the oil ch;uge in the chiller with the oil heater andcontrols energized to maintain the minimum oil reservoirtemperature.After Extended Shutdown -- Ensure the water sys-tem drains ;u'e closed. It may be advisable to flush the watercircuits to remove any soft rust which may have formed. Thisis a good time to brash the tubes and inspect the Schraderfittings 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 thechillel: [f (after adjusting for ambient temperature changes) anyloss in pressure is indicated, check for refrigerant leaks. SeeCheck Chiller Tightness section, page 53.Recharge the chiller by transferring refrigerant from thepumpout storage tank (if supplied). Follow the Pumpout andRefrigerant Transfer Procedures section, page 71. Observefreeze-up precautions.C;uefully make all legular 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. Ensme that the oil temperatme 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 thetemperature up. Piping may ;dso be arranged to bypass thecooling towel: The PIC llI controls have a low limit tower fanoutput that can be used to assist in this control (terminals 5 and6 on the TB2 haz;udous voltage field wiring terminal strip).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-;d operation is possible by overriding the tinget guide vaneposition. Access the COMPRESS screen on the ICVC andscroll down to highlight TARGET GUIDE VANE POS. Tocontrol the position, use the [INCREASE] or [DECREASE]softkey 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 the[RELEASEJ softkey.Similarly. the TARGET VFD SPEED can be manu;dly setin the COMPRESS screen. The target value is still limited to bebetween configured VFD MINIMUM SPEED and VFDMAXIMUM SPEED. Once speed is manually set in this man-nel, capacity control changes are directed to modulate theguide vanes.NOTE: Manual control mode overrides the configured pull-down ramp rate during st;ut-up and permits the guide vanes toopen at a faster rate. The PIC lII controls will close the guidevanes if the motor current exceeds the ACTIVE DEMANDLIMIT or capacity override limits. The guide vanes will_flso close if the chilled water temperature falls below theCONTROL POINT. For descriptions of capacity overrides andset points, see the Controls section.Refrigeration Log- A refrigeration log (as shown inFig. 38), is a convenient checklist for routine inspection andmaintenance and provides a continuous record of chillerperformance. It is also an aid when scheduling routine mainte-nance and diagnosing chiller problems.Keep a record of the chiller pressmes, temperatures, and liq-uid levels on a sheet similar to the one in Fig. 38. Automaticrecording of PIC [II data is possible by using CCN devicessuch as the Data Collection module and a Building Supervisol:Contact a C_urier representative for more information.69