Trane Understanding Run Inhibit in Chillers and Adaptive Control Manual Reset
Page 76

Machine Protection

and Adaptive

Control

Restart Inhibit.

This function provides short cycle protection for the motor, and indirectly also short cycling protection for the starter since the starter is designed to operate the motor under all the conditions of motor performance.

The operation of the restart inhibit function is dependent upon two setpoints. The Restart Inhibit Free Starts (1-5, 3 default), and the Restart Inhibit Start to Start Timer (10-30 min, 20 default). These settings are adjustable via the service tool.

Restart Inhibit Free Starts

This setting will allow a number of rapid restarts equal to its value. If the number of free starts is set to “1”, this will allow only one start within the time period set by the Start to Start Time Setting. The next start will be allowed only after the start to start timer has expired. If the number of free starts is programmed to “3”, the control will allow three starts in rapid succession, but thereafter, it would hold off on a compressor start until the Start to Start timer expired. i.e. with 3 free starts and 20 min. restart inhibit settings, it will take 60 minutes of run time to restore the total of 3 free starts.

Restart Inhibit Start to Start Time Setting

This setting defines the shortest chiller cycle period possible after the free starts have been used. If the number of free starts is programmed to “1”, and the Start to Start Time Setting is programmed to 10 minutes, then the compressor will be allowed one start every 10 minutes. The start-to-start time is the time from when the motor was commanded to energize to when the next command to enter prestart is given.

Clear Restart Inhibit

A Clear Restart Inhibit “button” is provided within Settings; Manual Override on the DynaView display. This provides a way for an operator to allow a compressor start when there is a currently active Restart Inhibit that is prohibiting such a start. The “button” press will have no other function than to remove the restart inhibit if there is one active. It does not change the count of any internal restart inhibit timers or accumulators. command, but is inhibited, pending the expiration of the timer.

The restart inhibit function, setpoints and clear features exist for each compressor and operate independently of other compressors on that chiller.

During the time the start is inhibited due to the start-to-start timer, the DynaView shall display the mode ‘Restart Inhibit’ and the also display the time remaining in the restart inhibit.

A “Restart Inhibit Invoked” warning diagnostic will exist when the attempted restart of a compressor is inhibited.

If all three motor winding temperatures are less than the “Restart Inhibit Temperature” Setpoint (default 165°F/74°C) then restart is allowed.

Restart inhibit mode exist when at least one of the three motor winding temperatures is greater than or equal to the “Restart Inhibit Temperature” Setpoint but less than 265°F/129.4°C. Restart inhibit mode is entered until all three motor winding temperatures are less than the ‘Restart Inhibit Temperature’ Setpoint

Note: When one of the three motor winding temperatures is 265°F/ 129.4°C or greater, a High Motor Winding Temperature diagnostic shall be called.

Note: When the start is inhibited by the restart inhibit function, the time remaining will be displayed along with the restart inhibit mode.

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Contents Operation Maintenance Read these carefully Contents General Information Literature changeAbout this manual Unit NameplateCVHF091NAL00ACU2758W7E8TB C0000000K01G14C10W1A03B1Commonly Used Acronyms Control Optional PackagesOverview CvhfGeneral Information General Information Cooling Cycle Cvhf CompressorCVHE, Cvhg pressure enthalpy curve Cvhf pressure enthalpy curve TechView Chiller Service Tool DynaView Human InterfaceCVHE, CVHF, and Cvhg sequence of operation running General Information Surface Temperatures Oil and Refrigeration PumpOil refrigerant pump Base Loading Control Algorithm 20 100 percent RLAGeneral Information Ice Machine Control Free Cooling Cycle Free Cooling Frcl Hot Gas Bypass Hot Water control Heat Recovery Cycle Auxiliary CondensersControl Panel Devices and Unit Mounted Devices Unit Control Panel UCPUnit 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 MinsecReference Main Screen Diagnostic Screen Back button provides navigation back to the chiller screen Operator Interface Reports Evaporator Report items Units Condenser Report Items UnitsCompressor Report Items Units Motor Report Items UnitsRPM Purge Report Items UnitsHistoric Diagnostics Log Ashrae Chiller Log UnitsRLA PPMChilled Water Setpoint Feature Settings Mode OverridesDescription Units Default Monitor Value ChillerDisplay Settings Description Units DefaultPurge Operator Interface Operator Interface Operator Interface Operator Interface Operator Interface Interprocessor Communication Inter Processor Communications IPC3IPC3 Definitions Bus Management BindingControl panel components layout and approximate dimensions Control System ComponentsControl System Components Control Panel Devices Machine Shutdown Manual Reset MMR Head Relief Request OutputCompressor Running Relay OpstRefrigerant Monitor Input 1A17 ExopFrcl Free Cooling Option Hgbp Hot Gas Bypass OptionTrmm TRM4 Tracer Comm 4 interface Cdrp Condenser Refrigerant Pressure OutputCondenser Pressure Output Temperature basedPressure based Refrigerant Differential Pressure Indication Output Gbas Gbas Generic Building Automation SystemPercent RLA Output Module Characteristics External Chilled Water Setpoint EcwsExternal Current Limit Setpoint Wpsr WFC Water Pressure Sensing Option1A8, 1A9, 1A11, 1A12 Quad Relay Output Status 1A13, 1A18, 1A19, 1A20 Dual Binary input module1A14 Communication interface Module Comm +1A15, 1A16, 1A17, 1A21 Dual Analog Input/output Module Recommended Length to Run external Output signalsAnalog Input Unit mounted devices Electrical Sequence Control Sequence of OperationUCP and Wye-Delta Starter Control Circuits Delay time 200 msec. Opens 2K1 Control Sequence of Operation Test and start timing sequence AFD Momentary Power Loss MPL Protection Machine Protection Adaptive ControlCurrent Overload Protection Overload trip time versus percent RLACurrent Limit Protection Phase Loss ProtectionReverse Rotation Protection SoftLoading Differential to Start or StopMinimum and Maximum Capacity Limit Leaving Water Temperature Cutout Evaporator Limit Low Refrigerant Temperature Cutout Main Processor Software Revision 6.0 and higherCutout strategy Evaporator Variable Flow Compensation Condenser LimitRestart Inhibit Start to Start Time Setting Restart InhibitRestart Inhibit Free Starts Clear Restart InhibitHigh Vacuum Lockout Oil Temperature Control Controls Chilled Water Reset CWR Outdoor Air TemperatureMaximum Reset Return WaterValues for start reset types Degrees of ResetConstant Return EquationReset Ratio Outdoor air temperature versus degrees of resetReset function for return CWR Reset Ratio = 50% Return CWR Unit Startup Unit Start-Up ProceduresDaily Unit Start-Up Before changeover to heating mode Live Electrical ComponentsToxic Hazards Seasonal Unit Start-UpUnit Shutdown Procedures Unit ShutdownOil Pump Heater Operation Seasonal Unit ShutdownPeriodic Maintenance Daily Maintenance and ChecksMoisture Contamination Record Keeping FormsWeekly Maintenance Normal Chiller Operating CharacteristicsHazardous Voltage w/ Capacitors Every 3 MonthsOff-Season Maintenance Annual MaintenanceOil Maintenance Oil Change ProcedureHeater Damage Compressor Oil Change onOil Filter Replacement Replacing Oil FilterMaintenance Oil Supply System ProblemsOther Maintenance Requirements LubricationDo not Leave Grease Fittings Installed Front View with Refrigerant PumpContains Refrigerant Refrigerant ChargeRecovery and Recycle Connections Leak TestingCleaning the Condenser Proper Water TreatmentControl Settings Adjustments Cleaning the EvaporatorUnit Corrosion Damage Purge System Unit PreparationHazardous Voltage w/ Capacitors 100 101 102 103 104 105 106 107 108 109 110 111 Trane
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