American Standard CH530 manual Fixed Sequence Compressor 2 / Compressor

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General Information

Fixed Sequence – Compressor 2 / Compressor 1

If the chiller is in the Auto mode and all interlocks have been satisfied, compressor 2 will be started based on the leaving water temperature rising above the “Differential to Start” setting. Compressors 1 will stage on when the overall chiller average capacity exceeds Stage on Load point for 30 seconds. The stage on load point is adjustable up to 50%. The default is 40% which means that a single compressor would have to

starts. Both compressors will run until chiller average capacity drops below Stage off Load point for 30 seconds. The stage off load point is also adjustable. Compressor 1 will be shut down and compressor 2 will run until water temperature drops below the differential to stop. Before shutting down, compressor 1 will be unloaded and compressor 2 will be loaded to maintain the same average capacity command.

If chilled water reset is used, the upstream compressor usually will be the most efficient compressor to operate at part load. If the leaving water temperature is reset and the chiller only needs one compressor, then the upstream compressor would be running closer to its selection point and will be the most efficient compressor to operate.

load to 80% (the average would be 40%) before the second compressor

Figure 13. CDHE/F/G sequence of operation: lead 2 lag 1

18	CDHF-SVU01C-EN

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Contents X39640670030CDHF-SVU01C-EN Read these carefully Contents About this manual General InformationLiterature change Unit NameplateGeneral Information = 560 3 stage 935 2 stage Y = 500 3 stage 835 2 stage Commonly Used Acronyms Control Optional PackagesOverview General Duplex unit components front viewGeneral Duplex unit components 2 stage compressor Cooling Cycle Compressor 1 or 2 2 StagePressure enthalpy curve 3 stage compressor Pressure enthalpy curve 2 stage compressor TechView Chiller Service Tool DynaView Human InterfaceSoftware States Figure Power Up DiagramSoftware Operation Overview Diagram Timeline Text FiguresCDHE/F/G sequence of operation auto to running Staging Second Compressor OnStaging Second Compressor Off Satisfied SetpointCDHF/G sequence of operation lead 1/lag Fixed Sequence Compressor 2 / Compressor CDHE/F/G sequence of operation lead 2 lagSequencing Balanced Starts and Hours CDHF/G sequence of operation equalize starts and hoursSimultaneous Compressor Start/ Stop CDHF/G sequence of operation combined startRestart Inhibit Free Starts Restart Inhibit Start to Start Time SettingRestart Inhibit Clear Restart InhibitSurface Temperatures Oil and Refrigerant PumpOil refrigerant pump circuit 1 or Base Loading Control Algorithm 20 100 percent RLAGeneral Information Ice Machine Control Sequence of operation ice making running to ice makingHot Water control Unit Control Panel UCP Control Panel Devices and Unit Mounted DevicesUnit Control Panel UCP Variable water flow through the evaporator User-defined language supportOperator Interface DynaView main processorOperator Interface Chiller Stop Prevention/Inhibit Feature How It WorksTop Level Mode Description System Reset Reference Main Screen Chiller Operating ModeCircuit Operating Mode Main Screen Data Fields TableDiagnostic Screen Back button provides navigation back to the chiller screen Operator Interface Report Menu ReportsReport name System Condenser Report name System EvaporatorReport name Circuit Evaporator Report name Circuit CondenserHistoric Diagnostics Log Report name System Ashrae Chiller LogSetting Tab screens provides a user Header ScreenFeature Settings ChillerDisplay Settings System Mode OverridesCircuit Mode Overrides PurgeOperator Interface Operator Interface Operator Interface Operator Interface Operator Interface IPC3 Definitions Bus Management Interprocessor CommunicationInter Processor Communications IPC3 BindingControl System Components Control panel components layoutControl System Components Control Panel Devices Maximum Capacity Relay Machine Shutdown Manual Reset MMRHead Relief Request Output Compressor Running RelayRefrigerant Monitor Input 1A17 ExopTrmm TRM4 Tracer Comm 4 interface Cdrp Condenser Refrigerant Pressure OutputEpro Enhanced Protection Condenser Pressure Output Temperature basedCdrp Refrigerant Pressure Output Option 1A15 Pressure basedRefrigerant Differential Pressure Indication Output Gbas Generic Building Automation System Percent RLA OutputExternal Current Limit Setpoint Module CharacteristicsExternal Chilled Water Setpoint Ecws Wpsr WFC Water Pressure Sensing Option1A8, 1A9, 1A11, 1A12 Quad Relay Output Status 1A13, 1A18, 1A19, 1A20 Dual Binary input module1A14 Communication interface Module Recommended Length to Run external Output signals 1A15, 1A16, 1A17, 1A21 Dual Analog Input/output ModuleAnalog Input Unit mounted devices Control System Components Control System Components Control Sequence of Operation Electrical SequenceUCP and Wye-Delta Starter Control Circuits Delay time 200 msec. Opens 2K1 Control Sequence of Operation Control Sequence Operation Test and start timing sequenceAFD Momentary Power Loss MPL Protection Machine Protection Adaptive ControlCurrent Overload Protection Overload trip time versus percent RLAPhase Loss Protection Current Limit ProtectionReverse Rotation Protection Differential to Start or Stop SoftLoadingMinimum and Maximum Capacity Limit Leaving Water Temperature Cutout Evaporator LimitLow Refrigerant Temperature Cutout Head Relief RelayCutout strategy Condenser Limit Restart Inhibit High Vacuum Lockout Oil Temperature Control Maximum Reset Controls Chilled Water Reset CWROutdoor Air Temperature Return WaterConstant Return Values for start reset typesDegrees of Reset EquationReset Ratio Outdoor air temperature versus degrees of resetReset function for return CWR Reset Ratio = 50% Return CWR Unit Start-Up Procedures Unit StartupDaily Unit Start-Up Seasonal Unit Start-Up Live Electrical ComponentsToxic Hazards ModeOil Pump Heater Operation Unit Shutdown ProceduresUnit Shutdown Seasonal Unit ShutdownMoisture Contamination Periodic MaintenanceDaily Maintenance and Checks Record Keeping FormsHazardous Voltage w/Capacitors Weekly MaintenanceNormal Chiller Operating Characteristics Every 3 MonthsOff-Season Maintenance Annual MaintenanceHeater Damage Oil MaintenanceOil Change Procedure Compressor Oil ChangeOil Filter Replacement Replacing Oil FilterOther Maintenance Requirements MaintenanceOil Supply System Problems Hazardous Voltage w/ CapacitorsRotary valve in drain position Front View with Refrigerant PumpContains Refrigerant Refrigerant ChargeCleaning the Condenser Recovery and Recycle ConnectionsLeak Testing Proper Water TreatmentCleaning the Evaporator Control Settings AdjustmentsUnit Corrosion Damage Purge System Unit Preparation103 104 105 106 107 108 109 110 111 112 113 114 115 Trane