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203.743.6741 • 203.798.7313www.preferred-mfg.com
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FEEDWATER CENTEROverview
Boilerfeedwatercontrolsystemsareoftenthemostarchaiccontrolsinthesteamplant.Poorboilerwatersidecontrolcontributestoscaling,corrosion,andeventuallyhotspotsand tube failures.ThePreferredFeedwater Center can controlthesurgetank,Deaerator(DA)tank,transferpumps,and feedwater pumps (on-off orVSD) to improvewaterqualityandfeedwatersystemreliability.
BetterFeedwaterDeliveryControl• “Smart”PumpSequencing• PumpSpeeddemandbasedStart-Stop• HeaderPressurebasedStart-Stop• Lead-LagSequence• FieldAdjustableParameters
EasytoUse• “Overview”, “Alarm”, “Historical Trend” and “Setup”
displays enable informed initial setup and processassessment.
• In a single NEMA 4 wall-mounted enclosure, theFeedwater Center integrates amodem for off-sitemonitoring,RS485Modbus communications and 24VDCpowersupplies.
• Optional 10”Operator InterfaceTouchscreen (OIT)providesgraphicaloverviewsaswellasEthernetTCP/IPandBacNetIPcommunicationtoBASsystems.
EasytoOrder,StockandFieldUpgrade• Completesystemisorderedusingasinglepartnumber.• “PlugIn”optionboardscanbeusedtoupgradeasystem
inthefield.
Feedwater Center Control System
With the optional 10” color touch screen, trend screens are provided to make it easy to tune level and temperature loops.
Display brings plant overviews, outdoor reset, alarms and event status and setup displays
right to the operator’s touch.Standard Keypad/Display
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Smart Pump SequencingIn“headeredmode,”pumpsareautomaticallysequencedon/off to ensure that the number of pumps in servicemeetsthedemand.Ifanypumpfailstostartwhencalled,the Feedwater Center immediately starts another pumptoreplacethefaultedpump.Theoperatormaymanuallyselect the lead pump or allow the lead pump to rotateautomatically. Additionally, the total number of pumpsin servicemay be set automatically ormanually by theoperator or all pumps may be shutdown by a buildingautomationsystem(BAS)‘enable/disable’contactinput.
Easy Installation & SetupTheFeedwaterCenterintegratesModbuscommunications,relays,24VDCpowersupplies,andoutdoorresetfunctionsintoasinglewallmountablecontroller.Simplemenu-stylefill-in-the-blanks setup displays minimize commissioningandtrainingtime.
LCD Graphic DisplayLCDgraphicdisplaybringsplantoverviews,outdoorreset,alarms and event status and setup displays right to theoperator’stouch.
Alarms & Event SummaryUp to 200 alarms, system events and operator actionsarelistedin“firstinfirstout”orderwithatime/datestamp.Alarms includesystemfault,pump failureandbothoverandundertemperatureconditions.
Hard Manual BackupHardwired control switches and dials provide simplemanual control for easy troubleshooting and service.Eachpumphasanindividualspeeddemandbargraph,amanualspeeddemandoutputknob,andanauto/manualswitch.
Modbus Communication InterfaceAfactoryconfiguredRS485MODBUSinterfaceisavailableforbuildingautomationorSCADAsystemmonitoringandcontrol.
Optional FeaturesThe Feedwater Center has many features that can beaddedorremovedaccordingtoyourneeds.Thiscontrollerwasdesignedtoaccommodatetheneedsofany1-4pumpsystem.Itisabletorunwithasurgeandadeaeratortank(oroneofeach,ornone).Itaccommodates0-3transferpumpsand0-4feedwaterpumps.TheJC-FWC-FCcanbeusedinheaderedpumpapplicationsaswellasindividualfeedwaterpumps toeachboiler. TheJC-FWC-FCcanhaveallofthesefollowingsensors;
Temperature:CondensateReturnLineDATank
Pressure:DATankFeedwaterHeaderSteamHeaderMakeUpWater
Level:1DATank1SurgeTank
Flow:MakeUpWaterFlowCondensateReturnFlow
Aswellascontrolling thespeedsofup to three transferpumpsandfourboilerfeedpumps.TheFeedwaterCentercontrols a number of valves in order tomaintain levels/pressures/flowrateswithinthesystem.
Thefollowingvalvescanbemaintained:
DALevelValveDAPSIControlValveSurgeTankMakeUpWaterValveChemicalFeedPumpValve
Thissystemiseasilyconfiguredbyusingthemenudriveninitial set-up screens. No programming knowledge isrequired.
FEEDWATER CENTEROverview
Feedwater Center Control System shown with optional 10” color touch screen OIT
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FEEDWATER CENTERTouchScreenOverview
Tuning PageTuningpagesallowtheusertoviewcontrolloopsfortuningpurposes.HistoricaldataissavedtoacompactflashcardandcanbeviewedthroughaPC.
Touch Screen OverviewTheoptional10”OperatorInterfaceTerminal(OIT)touchscreenprovidesgraphicalrepresentationofcurrentsystemstatus.Pump status, level indication, and valve positionareallreadilyavailableonthesystemoverviewpage.
Setup ParametersAllparametersareavailablethroughthesetuppagesonthe touchscreen.System featuresandcontrol logicareadjusteddependingontheinitialsetupparameters.
Alarm PageThealarmandeventsscreenlistsallcurrentalarmsandallrecentcontrolevents.Thisscreenhelpsdiagnoseboilerbeforetheyimpactboileroperation.
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FEEDWATER CENTEROverview
JC-FWC-xxx -FC -NV -NS -NVS FieldDevice
Digital InputsFWPumpRunning 4 4 4 4 120VAC-(e.g.currentsensingrelay)BoilerRunning/CallForWater 4 4 4 4 120VAC-BLRRun/DrumLevelSwitchTPPumpRunning 3 3 120VAC-CSR/AuxContactMotorstarterDALowLevelCutoffSwitch 1 1 1 1 120VAC-LevelSwitchSTLowLevelCutoffSwitch 1 1 1 120VAC-LevelSwitchWaterSoftenerAlarm 1 1 1 1 120VAC-ContactFromSoftenerDisable 1 1 1 1 120VAC-ContactFromBAS
Analog InputsDALevel 1 1 1 1 4-20mALevelTransmitterDATemperature 1 1 1 Thermowell(partnumbers70610,70611)DAPSI 1 1 1 4-20mAPSITransmitter(partnumber7060X)FWHeaderPSI 1 1 1 1 4-20mAPSITransmitter(partnumber7060X)SteamPSI 1 1 1 4-20mAPSITransmitter(partnumber7060X)*MakeupFlow 1 1 1 4-20mAFlowMeterMakeupPressure 1 1 1 4-20mAPSITransmitter(partnumber7060X)Condensate Return Temperature 1 1 1 Thermowell(partnumbers70610,70611)CondensateReturnFlow 1 1 1 4-20mAFlowMeterSurgeTankLevel 1 1 4-20mALevelTransmitter
Digital OutputsFWPumpStart 4 4 4** 4** DryContact(closetostart)TPPumpStart 3 3 DryContact(closetostart)WaterSoftenerRegenCycle 1 1 1** DryContact(closetostart)
Analog OutputsFWPumpSpeed 4 4 4-20mAOutputTPPumpSpeed 3 4-20mAOutputSTMUWaterValve 1 1 4-20mAOutputChemFeedPump 1 1 1 4-20mAOutputDAPSIControlValve 1 1 1 4-20mAOutputDALevelControlValve 1 1 1 4-20mAOutput
ThePreferredFeedwaterCenterisavailableinfourmodels,eachwithdifferentcapabilities.Toselectthecorrectmodelforeachapplication, consult thehardwareconfigurations, input/outputsprovided,andsample specificationson thefollowingpages.
Catalog Number Description PWC Hardware
Configuration
JC-FWC-FC Full Control PWCN4-CDROOOA
JC-FWC-NV NoVSDs PWCN4-CDROxxA
JC-FWC-NS NoSurgeTank/TransferPumps PWCN4-CDHOOxA
JC-FWC-NVS NoVSDsandnoSurgeTank/TransferPump PWCN4-CDHxxxx
BelowisacompletelistoftheinputsandoutputsforeachofthefourFeedwaterCentermodels.
*Steam PSI transmitter must be scaled similar to the Feedwater PSI transmitter**HOA switches provided on -NS and -NVS models
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FEEDWATER CENTERSpecifications
Mechanical:EnclosureSize: 35”Hx20”Wx10”DEnclosureType: Wallmount,NEMA4MountingHolePattern: (4)5/16”dia.Weight: 70lbs.
EnvironmentalOperatingTemp: 32°to122°F(0°to50°C)StorageTemp: -20°to150°F(-28°to65°C)HumidityLimits: 15%to95%(noncondensing)Enclosure: NEMA4
PerformanceAccuracy: 0.025%analogI/OResolution: 16bitinput/12bitoutputMicroprocessor: 32bit,128kEEPROMExecutionCycle: FivepersecondTime/DateClock: (batterybacked)
Operator Control PanelLCDDisplay: 2.9"Hx5.1"WKeyboard: Membrane,tactilefeedback
ConfigurationStandardLead/Lag: Menustyle
“Fill-In-The-Blanks”setup.ControlLanguage: Functionblockstyle,
60functions,600BlocksCustomBlockwareConfigurationSoftware: PWC_Edit™ spreadsheetbased
or PWC_Draw™ graphical,editor.(WindowsPCRequired)
CommunicationControlNetwork:Protocol: Modbus(ASCIIorRTUmode)Speed: 1200to38,400baudType: RS485,opticallyisolated
ProgrammingPort:Speed: 38,400baudType: RS232,DB9Fconnector
ElectricalInputPower: 120VAC(+/-15%),12Atotal,
0.7AinternalBuilt-insurgesuppressors
InternalPowerSupply: 24VDC@300mADCfor
external use
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FEEDWATER CENTER MODEL JC-FWC-FCFeedwaterDeliveryController
ApplicationTheFeedwaterCenterModel JC-FWC-FC includesallavailablefeatures and capabilities required to control feedwaterdeliverysystemsincludingDAlevelandpressurecontrol,surgetanklevelcontrol,transferpumpcontrol,feedwaterpump control, chemical feed pump control andwatersoftenerregeneration.
JC-FWC-FC, Full Control
Up to 4 Feedwater PumpsPumpsuse“smart”sequencingtoensurethepropernumberofpumpsarerunningtosatisfythefeedwaterdemand.
deaerator tank
surge tank
Boiler 1 Run (Boiler Limits, One per Boiler)
Surge Tank Make Up Water Valve
Surge Tank Low Level Sensor
DA Tank Level Control Valve
DA Tank Level
To Boilers (Header Piped or Optional Per Boiler Set Up)
DA Tank PSI
Chemical Feed Valve
Feedwater Pumps
Transfer Pumps
Condensate Return Line Temperature
DA Tank Temperature
FW H
eade
r PSI
Proof of FlowBoiler Feedwater Pump ONBoiler Feedwater Pump Speed Control
Proof of FlowTransfer Pump ONTransfer Pump Speed Control
DA Tank PSI Control Valve
DA Tank Low Level Sensor
PT LT TELS
PS
Chem
ical F
eed
Make Up Water Line
Water Softener
Typical Per Pump
Typical Per Pump
Condensate Return Line Flow
Steam Header Pressure
LS
Surge Tank Level
LTPT FT
Make Up Water PSIMake Up Water Flow
Soft Water Regen
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FEEDWATER CENTER MODEL JC-FWC-FCFeedwaterDeliveryController-Specification
1. ApplicationSupplyafullyintegratedFeedwaterControlsystemtocoordinatetheoperationof(upto)fourVSDcontrolledFeedwaterpumps,Daearatorlevelandpressurecontrol,(upto)threetransferpumps,watersoftenerregenerationandchemicalfeed.Thecontrolsystemshallbemicroprocessor-basedandsuitableforwallmounting.2. Pump VSD ModulationThecontrol systemshallprovideaPIDbasedcontrol scheme.Asdemandincreases,thespeedofthepumpwillincrease.Eachrunningpumpwillmodulateinunison.Modulationsignalsshallbe4-20mADCandshallbeelectricallyisolatedchannel-channelandchannel-ground.3. Headered Feedwater Pressure SetpointTheFeedwaterpressuresetpointmustbefieldselectablebetweensteamheaderbasedormanual.Insteamheaderbasedmode,theFeedwaterpressuresetpointmustbecalculatedbasedonanadjustabledeviationfromtheactualsteamheaderpressure.Inmanual, theoperatormaysettheFeedwaterHeaderPressureSetpointviaafrontpaneldisplay.4. Pump SequenceThecontrolsystemshallusebothFeedwaterheaderpressure(Deaerator level for transfer pumps) andpumpspeed to startandstopthepumpsandminimizethetotalnumberofpumpsinoperation.Thecontroller shall startandstoppumpswhen theFeedwaterheaderpressureisoutsideanadjustablepressurelimitbandforlongerthananadjustableshorttimedelay.Toanticipateandminimize header pressure deviations, the control systemshallstartorstopthenextpumpifthe“lead”pumphasbeennearmaximumorminimumspeedforlongerthantheadjustabletimedelay.Thecontrolsystemshallmonitoreachpump’sflowswitchandshallrapidlyandautomaticallyreplaceanypumpthatfailsto prove flow.The leadpumpshall either automatically rotateonatimeofday/dayofweek(ormonth)schedule,orshallbemanuallyselectedbytheoperator.Thecontrolsystemshallbefieldadjustableto“perboiler”modewhichwouldrunonefeedwaterpumpper boiler.Additionally, the control systemshall be fieldadjustabletochoosebetweenheaderedorboilerspecificpipingtodeterminewhichpumpsshouldbestarted.A120VACDiscreteinputistobeprovidedasaDeaeratorlowlevelsignalthatdisablesallFeedwaterPumps.A120VACDiscreteinputistobeprovidedasasurgetanklowlevelsignalthatdisablesalltransferpumps.5. Deaerator ControlThecontrolsystemshalloutputademandsignalbasedonDALevel. When usedwith transfer pumps, this is the speed atwhichthetransferpumpsmustrun.Withouttransferpumps,thiswoulddrivealevelcontrolvalve.ThecontrolsystemshalldriveaDeaeratorpressurecontrolvalvebasedonDeaeratorpressure.6. Surge Tank ControlThe control system shall output a command to a freshwatermakeupvalvebasedonsurgetanklevel.Fieldadjustablelevelforvalveat0%openandvalveat100%openshallbeprovided.
7. Chemical Feed ControlThecontrolsystemshallmonitormakeupwaterflowandsendthatflowsignaltoachemicalfeedpump.8. Soft Water Regeneration ControlThecontrolsystemshallinitiateasoftwaterregenerationcyclebasedontime,oruponreceivingasoftwateralarm.Theoperatorshall alsobeable to initiate the softwater regeneration cyclemanually.9. Monitor PointsThecontrolsystemshallmonitorDeaerator temperature, freshwatermakeuppressure,condensatereturnflowandcondensatereturntemperaturefordisplaypurposes.10. Operator Controls, Trends, Indications and AlarmsThe control system shall include a 16 line x 40 character (orgreater)LCDdisplayforboilersequencecontrolandstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,eventsandoperatoractionsshallbeloggedwithtime/datestampandEnglishlanguagedescription.11. CommunicationTheControl System shall have the ability of simultaneouslycommunicating to aDataAcquisitionSystem (DAS),BuildingAutomation System (BAS) or BuildingManagement System(BMS)viaRS485Modbusprotocolandtoapersonalcomputer.Theindividualboilerlimits,lockout,start/stop,warmstandby,andfiringratestatusshallbeeasilyread.Headersetpoint,plantfiringrate,boilerquantitycalledtostart,boilerselectedasleadandallsetupparametersshallbereadableandwritable.12. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements(CSAC22.2#14foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).Thecontrol systemshall beaPreferred Instruments,Danbury,CT,Model JC-FWC-FC.
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FEEDWATER CENTER MODEL JC-FWC-NVFeedwaterDeliveryController
ApplicationTheFeedwaterCenterModel JC-FWC-NV includesallavailablefeatures and capabilities required to control feedwaterdeliverysystemsincludingDAlevelandpressurecontrol,surgetanklevelcontrol,transferpumpcontrol,feedwaterpump control, chemical feed pump control andwatersoftenerregeneration.
JC-FWC-NV, Full Control for pumps without VSDs
Up to Four Feedwater PumpsPumpsuse“smart”sequencingtoensurethepropernumberofpumpsarerunningtosatisfythefeedwaterdemand.
deaerator tank
surge tank
Boiler 1 Run (Boiler Limits, One per Boiler)
Surge Tank Make Up Water Valve
Surge Tank Low Level Sensor
DA Tank Level Control Valve
DA Tank Level
To Boilers (Header Piped or Optional Per Boiler Set Up)
DA Tank PSI
Chemical Feed Valve
Feedwater Pumps
Transfer Pumps
Condensate Return line Temperature
DA Tank Temperature
FW H
eade
r PSI
Proof of FlowBoiler Feedwater Pump ON
Proof of flowTransfer Pump ON
DA Tank PSI Control Valve
DA Tank Low Level Sensor
PT LT TE
LS
PS
Chem
ical F
eed
Make Up Water Line
Water Softener
Typical Per Pump
Typical Per Pump
Condensate Return line Flow
Steam Header Pressure
LS
Surge Tank Level
LTPT FT
Make Up Water PSIMake Up Water Flow
Soft Water Regen
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FEEDWATER CENTER MODEL JC-FWC-NVFeedwaterDeliveryController-Specification
1. ApplicationSupplyafullyintegratedFeedwatercontrolsystemtocoordinatetheoperationof(upto)fourFeedwaterpumps,Daearatorlevelandpressurecontrol,(upto)threetransferpumps,watersoftenerregeneration and chemical feed.The control system shall bemicroprocessor-basedandsuitableforwallmounting.2. Headered Feedwater Pressure SetpointTheFeedwaterpressuresetpointmustbefieldselectablebetweensteamheaderbasedormanual.Insteamheaderbasedmode,theFeedwaterpressuresetpointmustbecalculatedbasedonanadjustabledeviationfromtheactualsteamheaderpressure.Inmanual,theoperatormaysettheFeedwaterheaderpressuresetpointviaafrontpaneldisplay.3. Pump SequenceThe control system shall use Feedwater Header Pressure(Deaerator Level for Transfer Pumps) to start and stop thepumpsandminimize the total number of pumps in operation.Thecontrollershallstartandstoppumpswhen theFeedwaterheaderpressureisoutsideanadjustablepressurelimitbandforlongerthananadjustableshorttimedelay.Thecontrolsystemshallmonitor each pump’s flow switch and shall rapidly andautomaticallyreplaceanypumpthatfailstoproveflow.Theleadpumpshalleitherautomaticallyrotateonatimeofday/dayofweek(ormonth)schedule,orshallbemanuallyselectedbytheoperator.Thecontrolsystemshallbefieldadjustableto“perboiler”modewhichwouldrunonefeedwaterpumpperboiler.Additionally,thecontrolsystemshallbefieldadjustabletochoosebetweenheadered or boiler specific piping to determinewhich pumpsshouldbestarted.A120VACDiscreteinputistobeprovidedasaDeaeratorlowlevelsignalthatdisablesallFeedwaterpumps.A120VACDiscreteinputistobeprovidedasasurgetanklowlevelsignalthatdisablesalltransferpumps.4. Deaerator ControlThecontrolsystemshalloutputademandsignalbasedonDAlevel.Whenusedwithtransferpumps,thisisthespeedatwhichthetransferpumpsmustrun.Withouttransferpumps,thiswoulddrivealevelcontrolvalve.ThecontrolsystemshalldriveaDeaeratorpressurecontrolvalvebasedonDeaeratorpressure.5. Surge Tank ControlThe control system shall output a command to a freshwatermakeupvalvebasedonsurgetanklevel.Fieldadjustablelevelforvalveat0%openandvalveat100%openshallbeprovided.6. Chemical Feed ControlThecontrolsystemshallmonitormakeupwaterflowandsendthatflowsignaltoachemicalfeedpump.7. Soft Water Regeneration ControlThecontrolsystemshallinitiateasoftwaterregenerationcyclebasedontime,oruponreceivingasoftwateralarm.Theoperatorshall alsobeable to initiate the softwater regeneration cyclemanually.
8. Monitor PointsThecontrolsystemshallmonitorDeaerator temperature, freshwatermakeuppressure,condensatereturnflowandcondensatereturntemperaturefordisplaypurposes.9. Operator Controls, Trends, Indications and AlarmsThe control system shall include a 16 line x 40 character (orgreater)LCDdisplayforboilersequencecontrolandstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,eventsandoperatoractionsshallbeloggedwithtime/datestampandEnglishlanguagedescription.10. CommunicationThe control system shall have the ability of simultaneouslycommunicating to aDataAcquisitionSystem (DAS),BuildingAutomation System (BAS) or BuildingManagement System(BMS)viaRS485Modbusprotocolandtoapersonalcomputer.Theindividualboilerlimits,lockout,start/stop,warmstandby,andfiringratestatusshallbeeasilyread.Headersetpoint,plantfiringrate,boilerquantitycalledtostart,boilerselectedasleadandallsetupparametersshallbeeasilyreadandwritten.11. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements(CSAC22.2#14foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).Thecontrol systemshall beaPreferred Instruments,Danbury,CT,Model JC-FWC-NV.
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FEEDWATER CENTER MODEL JC-FWC-NSFeedwaterDeliveryController
ApplicationTheFeedwaterCenterModel JC-FWC-NS includesallavailablefeatures and capabilities required to control feedwaterdeliverysystemsincludingDAlevelandpressurecontrol,feedwaterpumpcontrol,chemicalfeedpumpcontrolandwatersoftenerregeneration.
JC-FWC-NS, Full Control for systems without surge tanks
Up to Four Feedwater PumpsPumpsuse“smart”sequencingtoensurethepropernumberofpumpsarerunningtosatisfythefeedwaterdemand.
deaerator tank
Boiler 1 Run (Boiler Limits, One per Boiler)
DA Tank Level Control Valve
DA Tank Level
To Boilers (Header Piped or Optional Per Boiler Set Up)
DA Tank PSI
Chemical Feed Valve
Feedwater Pumps
Condensate Return Line Temperature
DA Tank Temperature
FW H
eade
r PSI
Proof of FlowBoiler Feedwater Pump ONBoiler Feedwater Pump Speed Control
DA Tank PSI Control Valve
DA Tank Low Level Sensor
PT LT TE
LS
PS
Chem
ical F
eed
Make Up Water Line
Water Softener
Typical Per Pump
Condensate Return Line Flow
Steam Header Pressure
PT FT
Make Up Water PSIMake Up Water Flow
Soft Water Regen
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FEEDWATER CENTER MODEL JC-FWC-NSFeedwaterDeliveryController-Specification
1. ApplicationSupplyafullyintegratedFeedwatercontrolsystemtocoordinatetheoperationof(upto)fourVSDcontrolledFeedwaterpumps,Daearatorlevelandpressurecontrol,watersoftenerregenerationandchemicalfeed.Thecontrolsystemshallbemicroprocessor-basedandsuitableforwallmounting.2. Pump VSD ModulationThecontrol systemshallprovideaPIDbasedcontrol scheme.Asdemandincreases,thespeedofthepumpwillincrease.Eachrunningpumpwillmodulateinunison.Modulationsignalsshallbe4-20mADCandshallbeelectricallyisolatedchannel-channelandchannel-ground.3. Headered Feedwater Pressure SetpointTheFeedwaterpressuresetpointmustbefieldselectablebetweensteamheaderbasedormanual.Insteamheaderbasedmode,thefeedwaterpressuresetpointmustbecalculatedbasedonanadjustabledeviationfromtheactualsteamheaderpressure.Inmanual, theoperatormayset theFeedwaterheaderpressuresetpointviaafrontpaneldisplay.4. Pump SequenceThecontrolsystemshallusebothFeedwaterheaderpressureandpumpspeedtostartandstopthepumpsandminimizethetotal number of pumps in operation.The controller shall startandstoppumpswhentheFeedwaterheaderpressureisoutsideanadjustablepressurelimitbandforlongerthananadjustableshort timedelay.Toanticipate andminimizeheader pressuredeviations,thecontrolsystemshallstartorstopthenextpumpifthe“lead”pumphasbeennearmaxorminspeedforlongerthantheadjustabletimedelay.Thecontrolsystemshallmonitoreachpump’sflowswitchandshall rapidlyandautomaticallyreplaceanypump that fails to prove flow.The leadpumpshall eitherautomatically rotateona timeofday/dayofweek (ormonth)schedule,or shall bemanually selectedby theoperator. Thecontrolsystemshallbefieldadjustableto“perboiler”modewhichwouldrunonefeedwaterpumpperboiler.Additionally,thecontrolsystemshallbefieldadjustabletochoosebetweenheaderedorboilerspecificpipingtodeterminewhichpumpsshouldbestarted.A120VACDiscreteinputistobeprovidedasaDeaeratorlowlevelsignalthatdisablesallFeedwaterpumps.5. Deaerator ControlThecontrolsystemshall triggerademandsignalbasedonDALevel.When usedwith transfer pumps, this is the speed atwhichthetransferpumpsmustrun.Withouttransferpumps,thiswoulddrivealevelcontrolvalve.ThecontrolsystemshalldriveaDeaeratorpressurecontrolvalvebasedonDeaeratorpressure.6. Chemical Feed ControlThecontrolsystemshallmonitormakeupwaterflowandsendthatflowsignaltoaChemicalfeedpump.7. Soft Water Regeneration ControlThecontrolsystemshallinitiateasoftwaterregenerationcyclebasedontime,oruponreceivingasoftwateralarm.Theoperatorshallalsobeabletomanuallystartthesoftwaterregenerationcycle.
9. Monitor PointsThecontrolsystemshallmonitorDeaerator temperature, freshwatermakeuppressure freshwatermakeup flow, condensatereturn flow and condensate return temperature for displaypurposes.10. Operator Controls, Trends, Indications and AlarmsThe control system shall include a 16 line x 40 character (orgreater)LCDdisplayforboilersequencecontrolandstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,eventsandoperatoractionsshallbeloggedwithtime/datestampandEnglishlanguagedescription.11. ReliabilityIncludehardwiredbackupstations topermitmanual operationoftheplantshouldthecontrolsystemrequireservice.Manualoperationmust be possiblewhen themicroprocessor is notfunctioning.Hardwired “hand-off-auto” control switchesmustbewireddirectlyintoeveryboilerstart/stopcircuit.Each4-20mADCor0-135ohmmodulatingcontroloutputmust includeahardwiredmanualbackupstationwithauto/manualswitch,outputcontrolknobandoutputlevelindicator(bargraph,analogmeterordigitaldisplay).12. CommunicationThe control system shall be capable of simultaneouslycommunicating to aDataAcquisitionSystem (DAS),BuildingAutomation System (BAS) or BuildingManagement System(BMS)viaRS485Modbusprotocolandtoapersonalcomputer.Theindividualboilerlimits,lockout,start/stop,warmstandby,andfiringratestatusshallbeeasilyread.Headersetpoint,plantfiringrate,boilerquantitycalledtostart,boilerselectedasleadandallsetupparametersshallbeeasilyreadandwritten.13. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements(CSAC22.2#14foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).Thecontrol systemshall beaPreferred Instruments,Danbury,CT,Model JC-FWC-NS.
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FEEDWATER CENTER MODEL JC-FWC-NVSFeedwaterDeliveryController
ApplicationThe Feedwater CenterModel JC-FWC-NVS includes allavailable features and capabilities required to controlfeedwaterpumps.
JC-FWC-NVS, Full Control for systems without surge tank or VSD controlled pumps
Up to Four Feedwater PumpsPumpsuse“smart”sequencingtoensurethepropernumberofpumpsarerunningtosatisfythefeedwaterdemand.
deaerator tank
Boiler 1 Run (Boiler Limits, One per Boiler)
DA Tank Level
To Boilers (Header Piped or Optional Per Boiler Set Up)
Feedwater Pumps
FW H
eade
r PSI
Proof of FlowBoiler Feedwater Pump ON
DA Tank Low Level Sensor
LT
LSPS
Typical Per Pump
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FEEDWATER CENTER MODEL JC-FWC-NVSFeedwaterDeliveryController-Specification
1. ApplicationSupplyafullyintegratedFeedwatercontrolsystemtocoordinatetheoperationof(upto)fourFeedwaterpumps.Thecontrolsystemshallbemicroprocessor-basedandsuitableforwallmounting.2. Headered Feedwater Pressure SetpointTheFeedwaterpressuresetpointmustbefieldselectablebetweenSteamheaderbasedormanual.Insteamheaderbasedmode,theFeedwaterpressuresetpointmustbecalculatedbasedonanadjustabledeviationfromtheactualSteamheaderpressure.Inmanual,theoperatormaysettheFeedwaterheaderpressuresetpointviaafrontpaneldisplay.3. Pump SequenceThecontrolsystemshalluseFeedwaterheaderpressuretostartandstopthepumpsandminimizethetotalnumberofpumpsinoperation.Thecontroller shall startandstoppumpswhen theFeedwaterheaderpressureisoutsideanadjustablepressurelimitbandforlongerthananadjustableshorttimedelay.Thecontrolsystemshallmonitoreachpump’sflowswitchandshallrapidlyandautomaticallyreplaceanypumpthatfailstoproveflow.Theleadpumpshalleitherautomaticallyrotateonatimeofday/dayofweek(ormonth)schedule,orshallbemanuallyselectedbytheoperator.Thecontrolsystemshallbefieldadjustableto“perboiler”modewhichwouldrunonefeedwaterpumpperboiler.Additionally,thecontrolsystemshallbefieldadjustabletochoosebetweenheadered or boiler specific piping to determinewhich pumpsshouldbestarted.A120VACDiscreteinputistobeprovidedasaDeaeratorlowlevelsignalthatdisablesallFeedwaterpumps.4. Operator Controls, Trends, Indications and AlarmsThe control system shall include a 16 line x 40 character (orgreater)LCDdisplayforboilersequencecontrolandstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,eventsandoperatoractionsshallbeloggedwithtime/datestampandEnglishlanguagedescription.Thecontrolsystemshallincludeaminimumof200pointmemory.5. ReliabilityIncludehardwiredbackupstations topermitmanual operationof theplantshould thecontrolsystemrequireservice.Manualoperationmust be possiblewhen themicroprocessor is notfunctioning.Hardwired “hand-off-auto” control switchesmustbewireddirectlyintoeveryboilerstart/stopcircuit.Each4-20mADCor0-135ohmmodulatingcontroloutputmust includeahardwiredmanualbackupstationwithauto/manualswitch,outputcontrolknobandoutputlevelindicator(bargraph,analogmeterordigitaldisplay).
6. CommunicationThe control system shall have the ability of simultaneouslycommunicating to aDataAcquisitionSystem (DAS),BuildingAutomation System (BAS) or BuildingManagement System(BMS)viaRS485Modbusprotocolandtoapersonalcomputer.Theindividualboilerlimits,lockout,start/stop,warmstandby,andfiringratestatusshallbereadable.Headersetpoint,plantfiringrate,boilerquantitycalledtostart,boilerselectedasleadandallsetupparametersshallbeeasilyreadandwritten.7. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements(CSAC22.2#14foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).Thecontrol systemshall beaPreferred Instruments,Danbury,CT,Model JC-FWC-NS.