American Standard CH530 manual Low Refrigerant Temperature Cutout, Head Relief Relay

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Machine Protection

and Adaptive

Control

Low Refrigerant Temperature Cutout

The purpose of the low evaporator refrigerant temperature protection is to prevent water in the evaporator from freezing. When the Low Evaporator Refrigerant Temperature Cutout (LRTC) trip point is violated, a latching diagnostic indicating the condition is displayed. The Low Evaporator Refrigerant Temperature Diagnostic is active in both the Running and Stopped modes.

The Low Evaporator Refrigerant Cutout Setpoint is factory set to 36°F. This can be altered via the service tool. A Service Tool adjustable setpoint that should be based on the percentage of antifreeze used in the customer’s water loop. The Service

tool will display a warning message such as “Warning: Adequate Antifreeze required” for any Evaporator Refrigerant Temperature Cutout below 28°F and any Leaving Water Temperature Cutout below 35°F.

The percent of antifreeze required is a function of the leaving water temperature setpoint and the worse case (lowest permitted water flow) approach temperatures of the chiller’s evaporator design.

Head Relief Relay

Surge, condenser limit, and certain conditions in ice mode can energize the head relief relay. Note: There is a TechView programmable head relief relay filter time setpoint. The default is 1 minute.

CDHF-SVU01C-EN

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Contents X39640670030CDHF-SVU01C-EN Read these carefully Contents Literature change General InformationAbout this manual Unit NameplateGeneral 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 ToolSoftware Operation Overview Diagram Power Up DiagramSoftware States Figure Timeline Text FiguresStaging 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/ StopRestart Inhibit Restart Inhibit Start to Start Time SettingRestart Inhibit Free Starts Clear Restart InhibitOil 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 Unit Control Panel UCPControl Panel Devices and Unit Mounted Devices 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 Circuit Operating Mode Chiller Operating ModeMain Screen Main Screen Data Fields TableDiagnostic Screen Back button provides navigation back to the chiller screen Operator Interface Reports Report MenuReport name Circuit Evaporator Report name System EvaporatorReport name System Condenser Report name Circuit CondenserReport name System Ashrae Chiller Log Historic Diagnostics LogHeader Screen Setting Tab screens provides a userChiller Feature SettingsCircuit Mode Overrides System Mode OverridesDisplay Settings PurgeOperator Interface Operator Interface Operator Interface Operator Interface Operator Interface Inter Processor Communications IPC3 Interprocessor CommunicationIPC3 Definitions Bus Management BindingControl panel components layout Control System ComponentsControl System Components Control Panel Devices Head Relief Request Output Machine Shutdown Manual Reset MMRMaximum Capacity Relay Compressor Running RelayExop Refrigerant Monitor Input 1A17Epro Enhanced Protection Trmm TRM4 Tracer Comm 4 interfaceCdrp Condenser Refrigerant Pressure Output Cdrp Refrigerant Pressure Output Option 1A15 Temperature basedCondenser Pressure Output Pressure basedRefrigerant Differential Pressure Indication Output Percent RLA Output Gbas Generic Building Automation SystemExternal Chilled Water Setpoint Ecws Module CharacteristicsExternal Current Limit Setpoint Wpsr WFC Water Pressure Sensing Option1A14 Communication interface Module 1A8, 1A9, 1A11, 1A12 Quad Relay Output Status1A13, 1A18, 1A19, 1A20 Dual Binary input module Analog Input Recommended Length to Run external Output signals1A15, 1A16, 1A17, 1A21 Dual Analog Input/output Module Unit mounted devices Control System Components Control System Components UCP and Wye-Delta Starter Control Circuits Control Sequence of OperationElectrical Sequence 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 Protection Reverse Rotation Protection Phase Loss Protection Current Limit Protection Minimum and Maximum Capacity Limit Differential to Start or StopSoftLoading Evaporator Limit Leaving Water Temperature CutoutHead Relief Relay Low Refrigerant Temperature CutoutCutout strategy Condenser Limit Restart Inhibit High Vacuum Lockout Oil Temperature Control Outdoor Air Temperature Controls Chilled Water Reset CWRMaximum Reset Return WaterDegrees of Reset Values for start reset typesConstant Return EquationOutdoor air temperature versus degrees of reset Reset RatioReset function for return CWR Reset Ratio = 50% Return CWR Daily Unit Start-Up Unit Start-Up ProceduresUnit Startup Toxic Hazards Live Electrical ComponentsSeasonal Unit Start-Up ModeUnit Shutdown Unit Shutdown ProceduresOil Pump Heater Operation Seasonal Unit ShutdownDaily Maintenance and Checks Periodic MaintenanceMoisture Contamination Record Keeping FormsNormal Chiller Operating Characteristics Weekly MaintenanceHazardous Voltage w/Capacitors Every 3 MonthsAnnual Maintenance Off-Season MaintenanceOil Change Procedure Oil MaintenanceHeater Damage Compressor Oil ChangeReplacing Oil Filter Oil Filter ReplacementOil Supply System Problems MaintenanceOther Maintenance Requirements Hazardous Voltage w/ CapacitorsFront View with Refrigerant Pump Rotary valve in drain positionRefrigerant Charge Contains RefrigerantLeak Testing Recovery and Recycle ConnectionsCleaning the Condenser Proper Water TreatmentUnit Corrosion Damage Cleaning the EvaporatorControl Settings Adjustments Unit Preparation Purge System103 104 105 106 107 108 109 110 111 112 113 114 115 Trane