American Standard CH530 manual Differential to Start or Stop, SoftLoading

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Machine Protection

and Adaptive

Control

Differential to Start or Stop

The Differential to Start setpoint is adjustable from 1 to 10°F (0.55 to 5.55°C) and the Differential to Stop setpoint adjustable from 1 to 10°F (0.55 to 5.55°C). Both setpoints are with respect to the Active Chilled Water Setpoint. When the chiller is running and the LWT (Leaving Water Temperature) reaches the Differential to Stop setpoint the chiller will go through its shutdown sequence to AUTO. (Refer to Figure 10.)

SoftLoading

Softloading stabilizes the startup control during the initial chiller pulldown. Soft loading is used to bring the building loop temperature from its start value to the Chilled Water or Hot Water Setpoint in a controlled manner. Without soft loading, the chiller controls will load the chiller rapidly and use the full chiller capacity to bring the loop temperature to setpoint. Although the start temperature of loop may have been high, the actual system load may be low. Thus, when the setpoint is met the chiller must unload quickly to the system load value. If it is not able to unload quickly enough, the supply water temperature will

drop below setpoint and may even cause the chiller to cycle off. Soft loading prevents the chiller from going to full capacity during the pulldown period. After the compressor has been started, the starting point of the filtered setpoint is initialized to the value of the Evaporator Leaving Water temperature and the percent RLA.

There are three independent Softload setpoints:

•Capacity Control Softload Time (default to 10 minutes, 0-120 minutes) This setting controls the time constant of the Filtered Chilled Water Setpoint.

•Current Limit Control Softload Time (default 10 minutes; 0-120 minutes) This Setting controls the time constant of the Filtered Current Limit Setpoint.

•Current Limit Softload Starting Percent (default is 40 percent RLA; 20-100 percent): This setting controls the Starting point of the Filtered Current Limit Setpoint

Service tool provides access to these three setpoints, if it is determined necessary to change from the defaults.

Softloading is not active during Ice Making or during the Ice To normal Transition. Softloading will be enabled after the Ice to normal Transition timer has expired.

Minimum and Maximum Capacity Limit

A Minimum Capacity can be set to limit the unloading ability of the compressor thus forcing differential to stop to be reached cycling the chillers. Minimum capacity limit will be displayed when in this limit mode. This indicates when the chiller is running fully unloaded.

Similarly a maximum capacity can be set to limit normal chilled water temperature control, the maximum capacity relay is energized which is a signal used by generic BAS systems to start another chiller.

The minimum (default at 0 percent) and maximum (default at 100 percent) capacity are adjustable via the service tool.

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Contents X39640670030CDHF-SVU01C-EN Read these carefully Contents Unit Nameplate General InformationLiterature change About this manualGeneral Information = 560 3 stage 935 2 stage Y = 500 3 stage 835 2 stage Control Optional Packages Commonly Used AcronymsGeneral Duplex unit components front view OverviewGeneral Duplex unit components 2 stage compressor Compressor 1 or 2 2 Stage Cooling CyclePressure enthalpy curve 3 stage compressor Pressure enthalpy curve 2 stage compressor DynaView Human Interface TechView Chiller Service ToolTimeline Text Figures Power Up DiagramSoftware Operation Overview Diagram Software States FigureStaging Second Compressor On CDHE/F/G sequence of operation auto to runningSatisfied Setpoint Staging Second Compressor OffCDHF/G sequence of operation lead 1/lag CDHE/F/G sequence of operation lead 2 lag Fixed Sequence Compressor 2 / CompressorCDHF/G sequence of operation equalize starts and hours Sequencing Balanced Starts and HoursCDHF/G sequence of operation combined start Simultaneous Compressor Start/ StopClear Restart Inhibit Restart Inhibit Start to Start Time SettingRestart Inhibit Restart Inhibit Free StartsOil and Refrigerant Pump Surface TemperaturesOil refrigerant pump circuit 1 or 20 100 percent RLA Base Loading Control AlgorithmGeneral Information Sequence of operation ice making running to ice making Ice Machine ControlHot Water control Unit Control Panel UCP Control Panel Devices and Unit Mounted DevicesUnit Control Panel UCP User-defined language support Variable water flow through the evaporatorDynaView main processor Operator InterfaceOperator Interface How It Works Chiller Stop Prevention/Inhibit FeatureTop Level Mode Description System Reset Reference Main Screen Data Fields Table Chiller Operating ModeCircuit Operating Mode Main ScreenDiagnostic Screen Back button provides navigation back to the chiller screen Operator Interface Reports Report MenuReport name Circuit Condenser Report name System EvaporatorReport name Circuit Evaporator Report name System CondenserReport name System Ashrae Chiller Log Historic Diagnostics LogHeader Screen Setting Tab screens provides a userChiller Feature SettingsPurge System Mode OverridesCircuit Mode Overrides Display SettingsOperator Interface Operator Interface Operator Interface Operator Interface Operator Interface Binding Interprocessor CommunicationInter Processor Communications IPC3 IPC3 Definitions Bus ManagementControl panel components layout Control System ComponentsControl System Components Control Panel Devices Compressor Running Relay Machine Shutdown Manual Reset MMRHead Relief Request Output Maximum Capacity RelayExop Refrigerant Monitor Input 1A17Trmm TRM4 Tracer Comm 4 interface Cdrp Condenser Refrigerant Pressure OutputEpro Enhanced Protection Pressure based Temperature basedCdrp Refrigerant Pressure Output Option 1A15 Condenser Pressure OutputRefrigerant Differential Pressure Indication Output Percent RLA Output Gbas Generic Building Automation SystemWpsr WFC Water Pressure Sensing Option Module CharacteristicsExternal Chilled Water Setpoint Ecws External Current Limit Setpoint1A8, 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 Test and start timing sequence Control Sequence OperationAFD Machine Protection Adaptive Control Momentary Power Loss MPL ProtectionOverload trip time versus percent RLA Current Overload ProtectionPhase Loss Protection Current Limit ProtectionReverse Rotation Protection Differential to Start or Stop SoftLoadingMinimum and Maximum Capacity Limit Evaporator Limit Leaving Water Temperature CutoutHead Relief Relay Low Refrigerant Temperature CutoutCutout strategy Condenser Limit Restart Inhibit High Vacuum Lockout Oil Temperature Control Return Water Controls Chilled Water Reset CWROutdoor Air Temperature Maximum ResetEquation Values for start reset typesDegrees of Reset Constant ReturnOutdoor air temperature versus degrees of reset Reset RatioReset function for return CWR Reset Ratio = 50% Return CWR Unit Start-Up Procedures Unit StartupDaily Unit Start-Up Mode Live Electrical ComponentsToxic Hazards Seasonal Unit Start-UpSeasonal Unit Shutdown Unit Shutdown ProceduresUnit Shutdown Oil Pump Heater OperationRecord Keeping Forms Periodic MaintenanceDaily Maintenance and Checks Moisture ContaminationEvery 3 Months Weekly MaintenanceNormal Chiller Operating Characteristics Hazardous Voltage w/CapacitorsAnnual Maintenance Off-Season MaintenanceCompressor Oil Change Oil MaintenanceOil Change Procedure Heater DamageReplacing Oil Filter Oil Filter ReplacementHazardous Voltage w/ Capacitors MaintenanceOil Supply System Problems Other Maintenance RequirementsFront View with Refrigerant Pump Rotary valve in drain positionRefrigerant Charge Contains RefrigerantProper Water Treatment Recovery and Recycle ConnectionsLeak Testing Cleaning the CondenserCleaning the Evaporator Control Settings AdjustmentsUnit Corrosion Damage Unit Preparation Purge System103 104 105 106 107 108 109 110 111 112 113 114 115 Trane
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