chief dispatcher modulating lead/lag controllers … · chief dispatcher modulating lead/lag...

203.743.6741 • 203.798.7313www.preferred-mfg.com

Instruments & Controls

Catalog 25

Instruments &

Controls

125

CHIEF DISPATCHER MODULATING LEAD/LAG CONTROLLERSOverview

BetterSteamorHotWaterSystemControl• Modelavailableforsteam,hotwater,andcondensing

boilers• “Smart”boilersequencingtoimproveresponsetime• Steamboiler"BaseLoadAuto-Shift”reducescycling• Hotwaterboiler“Header”or“Boiler”pumpsequencing• Firetube boiler thermal shock protection using blend

valves• Condensing boiler logicmaximizes lower firing rate

operationtoincreaseefficiency

EasytoUse• “PlantOverview,”“Alarm,”and“Setup”displaysenable

informedinitialsetupandprocessassessment• Inasinglewall-mountedenclosure,theChiefDispatcher

integrates amodem for off-sitemonitoring, RS485Modbuscommunications,24VDCpowersuppliesandoutdoorresetfunctions.Noexternalcontroldevicesarerequired

EasytoOrder,StockandFieldUpgrade• Completesystemisorderedusingasinglepartnumber• “PlugIn”optionboardscanbeusedtoupgradeasystem

inthefield

LCD Graphic Display

PlantOverviewDisplay(s)Ataglancecontrolandmonitoringofboilerstatusandlead/lagsequence.

Alarm/EventSummaryDisplayUpto200Alarms,eventsandoperatoractionsareloggedwithtime,datestamp,anddescription.

SetbackDisplay(s)SimpleDay/Night/WeekSetbacksetup.

OutdoorResetDisplayEasilyconfigurenormalandsetbacksetpointsandlimits.Agraphicalrepresentationisautomaticallygenerated.

BoilerSetupDisplaysSimpleMenustyle“Fill-In-The-Blanks”setup.



Catalog 25

Inst

rum

ents

& C

ontro

ls

126

“Smart” Boiler SequencingBoilersareautomaticallysequencedon/offtoensurethatthenumberofboilersinservicemeetssteamorhotwaterdemand.Ifanyboilerfailstostartwhencalled,orifaboilertripsduringoperation,thechiefdispatcherimmediatelystartsanotherboilertoreplacethe“faulted”boiler.Theoperatormaymanuallyselecttheleadboilerorallowtheleadboilertorotateautomatically.Additionally,thetotalnumberofboilersinservicemaybesetautomaticallyormanuallyasselectedbytheoperatororallboilersmaybeshutdownbyaBuildingAutomationSystem(BAS)“enable/disable”contactinput.

“Hard Manual” BackupHardwiredcontrolswitchesanddialsprovidesimplemanualcontrolforeasytroubleshootingandservice.Eachboilerhasanindividualfiringratebargraph,“manual”firingrateoutputknob,and“Auto/Manual’switch.

Modbus Communication InterfaceAfactoryconfiguredRS485ModbusinterfaceisavailableforBuildingAutomationorSCADAsystemmonitoringandcontrol.

Building Automation System (Option ‘-BAS’)AremoteHotWaterSupply(HWS)temperaturesetpointissetbyeitheraModbusor4-20mADCBuildingAutomationSystem(BAS)outdoorresetinputsignal.

Firing Rate Output (Option “-I” or “-P”)BoilerFiringRateAnalogOutputCardsmaybeorderedas‘-P’=0-135ohmor‘-I’=4-20mADC.

Spareterminals(typical)

Cabletiedowns

¾"conduitconnectionsPowerfuses

Physicalseparationbetweenoperationandwiring

FusedAuxiliary120VACPowerOutputs

CHIEF DISPATCHER MODULATING LEAD/LAG CONTROLLERSOverview

Chief Dispatcher with both doors open

PWC_Remote™ Software



Catalog 25

Instruments &

Controls

127

CHIEF DISPATCHER MODULATING LEAD/LAG CONTROLLERSSpecifications

MechanicalCaseSize: 10½"Hx18"Wx8½"DEnclosureType: WallmountedCase: 7Slot,(CPU+6I/OSlots)Weight: 55lbs.

EnvironmentalOperatingTemp: 32°to122°F(0°to50°C)StorageTemp: -20°to150°F(-28°to65°C)HumidityLimits: 15%to95%(noncondensing)Enclosure: NEMA1

PerformanceAccuracy: 0.025%AnalogI/OResolution: 16bitinput/12bitoutputMicroprocessor: 32bit,128kEEPROMExecutionCycle: FivepersecondTime/DateClock: (batterybacked)

Operator Control PanelLCDGraphicDisplay: 2.9"Hx5.1"WKeyboard: Membrane,tactilefeedback

ConfigurationStandardLead/Lag: Menustyle

“Fill-In-The-Blanks”setup.ControlLanguage: Functionblockstyle,

60functions,600BlocksSecurity: 2passwordlevelsCustomBlockwareConfigurationSoftware: 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,

0.7AinternalBuiltinsurgesuppressors

InternalPowerSupply: 24VDC@300mADCforexternal use

G

G

G

G

G

15 5/8"1 3/16"

18 " Wide (8 1/2 " Deep)

19 1

/4"

20 1

/8"

21 1

/8"

3/4" ConduitKnockouts

(typ. 7)

FAN

FUEL VALVE

LOCKOUT

BOILER 1

FAN

FUEL VALVE

LOCKOUT

BOILER 2

FANFUEL VALVELOCKOUT

BOILER 3

LOW FEEDWTR PSILOW FEED TANK LEV

MAN AUTO

BOILER 1

MAN AUTO

BOILER 2

MAN AUTO

BOILER 3

MAN AUTO

MAN AUTO

RUNCPU OK

FORCED

CPU Module

ALARM

BATTERY

COM 1

PROGRAMMINGPORT

Tx MODEM 1

Rx

CD

AA

Tx COM 2

Rx

LCD CONTRAST

BOILER 2

ON - OFF - AUTO

BOILER 1

BOILER 3

ON - OFF - AUTO

FEED PUMP 1

ON - OFF - AUTO

FEED PUMP 2

ON - OFF - AUTO

ON - OFF - AUTO

PREFERRED

INSTRUMENTS

ABC

1DEF

2GHI

3JKL

4MNO

5STU

7VWX

8YZ "

9% # ,

0: < >

./ + -

SPACE

PQR

6

PAGEDOWN

PAGEUP

MENU

HOMEPAGE

ESC ENTERALARMLIST

ALARMSILENCE



Catalog 25

Inst

rum

ents

& C

ontro

ls

128

CHIEF DISPATCHER MODEL JC-CDSTSteamBoilersModulatingLead/LagController

ApplicationTheChiefDispatcherModel JC-CDSToptimizes steamsystemperformanceandhelpsextendCastIronSectional,Finned-Tube,Firebox,FlexibleTubeorFiretubeboilerlife.

2 to 10 Modulating BoilersBoilerfiringratesareautomaticallyadjustedtosatisfytheoverallplantsteamheatingloadusingaccuratePIDcontrol.Whendesiredtheoperatormaysetthefiringratemanually.

Warm StandbyEachoff-lineboilerisperiodicallystartedandheldatlowfireuntilitreturnstothe“warmstandby”temperature(Aquastatsuppliedbyboilermanufacturer).Thishelps tominimizethermalshockwhencalledon-line.

Typical for all2 to 10 Boilers

JC-CDST2 to 10 Steam Boilers

“Base Load Auto-Shift”Normally,theLagboilersremainbaseloadedforpeaktotalplantefficiency.Iftheleadboilerfiringrateapproacheshighfire,thelagboiler(s)willincreasetheirfiringrateto“help”theleadboiler.Iftheleadboilerapproacheslowfire,thelagboilerswilldecreasetheirfiringrateto“help”theleadboiler.Thismethodminimizesboileron/offcyclingduetoshorttermloadswingswhilemaximizingtotalboilerplantefficiency.Ifdesired,“unison”modulationcanalsobefieldselected(allboilersfireatthesamerate).



Catalog 25

Instruments &

Controls

129

SpecificationsPanel DetailsController: PWCCaseSize: 19¼"HX18"WX8½"DEnclosureType: Wallmounted,Weight:55lbs.

InputsSteamPressure: 0to25PSI,0to200PSI,

or0to500PSI,4-20mADCBAS,BoilerDisable: 120VAC,opticallyisolatedLimits: 120VAC,opticallyisolated

(eachboiler)BoilerLockout: 120VAC,opticallyisolated

(eachboiler)WarmStandby: 120VAC,opticallyisolated

(eachboiler)OutputsModulation: Isolated4-20mADCor0-135ohm

(eachboiler)BoilerStart: Drycontact,8FLA,½HP,120VAC

(eachboiler)

CHIEF DISPATCHER MODEL JC-CDSTSteamBoilersModulatingLead/LagController

ManualFiringRateControlDialfor ModulatingOutputs

FiringRate“Auto/Manual”Switches

0-100%Bargraph

“On-Off-Auto”Switchesfor Contact Outputs

“On-Off”InputswithStatusLEDs10 Boiler Controller Front Panel ShownDiagnosticsand

CommunicationStatus

Order Sensors Separately(Quantity as Required)

CatalogNumber

SteamPressureSensor0-25PSIwithsyphonloop 70600





Catalog 25

Inst

rum

ents

& C

ontro

ls

130

CHIEF DISPATCHER MODEL JC-CDSTSuggestedSpecifications

1. ApplicationSupplyafullyintegratedboilercontrolsystemtocoordinatetheoperationoftwo(selectuptoten)fullymodulatingsteamboilersin order tomaintainSteamHeaderPressure at setpoint.Thecontrolsystemshallbemicroprocessor-basedandsuitable forwallmounting.2. Boiler ModulationThecontrol systemshallprovideaPIDbasedcontrol scheme.Modulation shall be field selectable as either “Unison” (all atthe same firing rate) or as “Series”. Seriesmodulation shallinclude“BaseLoadAuto-Shift”logicinordertominimizeboileron/offcycling.Normallythelagboilersshallbebaseloadedatanoperatoradjustablefiringrateforpeakefficiency.Whentheleadboiler’sfiringrateapproacheshighfire,thelagboiler(s)willautomaticallymodulateupfromthebaseloadfiringrateto“help”theleadboilerwithoutstartinganotherlagboiler.Iftheleadboilerapproacheslowfire,thelagboilerswillmodulatetowardlowfireto“help”theleadboilerandpreventashortcycleofalagboiler.Whentheleadboilerleavesthehighorlowfirepositionthelagboiler(s)resumefiringatthenormalbaseloadforpeakefficiency.Iftheloadincreaseordecreaseislongterm,alagboilershallbecycledonoroffasrequired.Modulationsignalsshallbe4-20mADCor 0-135 ohm (as required by the boiler) and shall beelectricallyisolatedchannel-channelandchannel-ground.3. Steam Header Pressure SetpointTheoperatormaysettheSteamHeaderPressureSetpointviaafrontpaneldisplay.4. Boiler SequenceThecontrolsystemshallusebothSteamHeaderPressureandBoilerFiringRatepercenttostartandstoptheboilersandminimizethetotalnumberofboilersinoperation.ThecontrollershallstartandstopboilerswhentheSteamHeaderPressureisoutsideanadjustablepressurelimitbandforlongerthananadjustableshorttimedelay.Toanticipateandminimizeheaderpressuredeviations,thecontrolsystemshallstartorstopthenextboilerifthe“lead”boilerhasbeennearhighorlowfireforlongerthantheadjustabletimedelay.Thecontrolsystemshallmonitoreachboiler’slockoutand limit circuits and shall rapidly andautomatically skip overthoseboilersthatarepowereddownformaintenance,trippedorotherwisewillnotstart.Theleadboilershalleitherautomaticallyrotateonatimeofday/dayofweek(ormonth)schedule,orshallbemanuallyselectedbytheoperator.Provideawarmstandbyboilershellaquastatinputforeachboiler.Ifrecommendedbytheboilermanufacturer,eachoff-lineboilershallbestartedandheldatlowfirewhenthetemperaturedrops.Whencalledtorun,theboilershallholdatlowfireuntilthetemperaturerisesabovethewarmstandbysetting.Provideanaquastatreleasetomodulateover-ridetimertopreventaprotractedlowfirehold.TheControlSystemshallreducethefiringratetoaminimumbeforestoppingaboilertopreventaccumulationoffuelinthefurnace.

5. Operator Controls, Trends, Indications and AlarmsThe control system shall include a 16 line x 40 character (orgreater)LCDdisplayforboilersequencecontrolandstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,eventsandoperatoractionsshallbeloggedwithtime/datestampandEnglishlanguagedescription.6. ReliabilityIncludehardwiredbackupstations topermitmanual operationoftheplantshouldthecontrolsystemrequireservice.Manualoperationmust be possiblewhen themicroprocessor is notfunctioning. Hardwired “hand-off-auto” control switchesmustbewireddirectlyintoeveryboilerstart/stopcircuit.Each4-20mADCor0-135ohmmodulatingcontroloutputmust includeahardwiredmanualbackupstationwithauto/manualswitch,outputcontrolknobandoutputlevelindicator(bargraph,analogmeterordigitaldisplay).7. CommunicationTheControl System shall have the ability of simultaneouslycommunicating to aDataAcquisitionSystem (DAS),BuildingAutomation System (BAS) or BuildingManagement System(BMS)viaRS485Modbusprotocol,andtoaPersonalComputer.Theindividualboilerlimits,lockout,start/stop,warmstandby,andfiringratestatusshallbereadable.Headersetpoint,plantfiringrate,boilerquantitycalledtostart,boilerselectedasleadandallsetupparametersshallbeeasilyreadandwritten.8. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements(CSAC22.2#14foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).ThecontrolsystemshallbeaPreferredInstruments,Danbury,CT,Model JC-CDST-x-P (‘x’=boilerquantityfrom2to10;“-P”for0-135ohm;“-I”for4-20mA).



Catalog 25

Instruments &

Controls

131

CHIEF DISPATCHER MODEL JC-CDHWHotWaterBoilersModulatingLead/LagController

ApplicationTheChiefDispatcherModelJC-CDHWoptimizeshotwatersystemperformanceandhelpsextendCastIronSectional,Finned-Tube,FireboxorFlexibleTubeboilerlife.

2 to 10 Fully Modulating BoilersHotWaterSupply(HWS)headertemperatureismaintainedusingaccuratePIDcontrol.Multipleboilersaremodulatedin“Unison”(allatthesamefiringrate)toensureevenheatdelivery.Lagboilersarebroughtuptothe“Unison”firingrateusingapredeterminedRampRatetomeettheheatingloadwithminimumovershoot.Whendesired,theoperatormaysetthe“unison”firingratemanually.

Outdoor ResetEnergyissavedbyloweringtheHotWaterSupply(HWS)temperature setpoint as the outside air temperatureincreases.Operatingcostisreducedduringwarmerdays.Whendesired, the operatormay set theHWSsetpointmanually.

Time of Day / Week SetbackThisfeatureisusedinheatingapplicationstosaveenergyby lowering theHotWaterSupply (HWS) temperaturesetpoint during timeswhen the heating requirement isreduced,suchasatnightoronweekendsandholidays.

JC-CDHW2 to 10 Hot Water Boilers

Domestic Hot Water Priority (2 to 9 boiler systems) A temperature switch (thermostat) contact closure inputwill override the “outdoor reset and “setback” portion oftheprogramandforcetheHWStemperaturesetpointtoadomestichotwatersetpoint.Arelayoutputisavailabletostartadomestichotwaterpumpifrequired.

Condensing Boiler Logic (option “-C”)Condensing boiler logic takes full advantage of thecondensing boiler design bymaximizing the number ofboilersrunningnearlowfiretomaximizeefficiency.

AI HOT WATER SUPPLY HEADER TEMPERATURE

Typical forEach Boiler



Catalog 25

Inst

rum

ents

& C

ontro

ls

132

CHIEF DISPATCHER MODEL JC-CDHWHotWaterBoilersModulatingLead/LagController


CatalogNumber

HotWaterThermistorTemperatureSensor0ºto300ºF,4½"depth 70610

Thermowell,SS,4½"x½"NPT 70610WOutsideAirThermistorTemperatureSensorwithweather-proofcover 70612

Optional Features CatalogNumber

BuildingAutomationSystem(BAS)4-20mADCSetpoint JC-CDHWxxx-BAS

CondensingBoilerLogic JC-CDHWxxx-C


InputsHotWaterTemperature: 0°to300°F,ThermistorOutdoorAirTemperature: Thermistor(non“BAS”version)BASResetSetpoint: 4-20mADC(“-BAS”version)BASBoilerDisable: 120VAC,opticallyisolated

(eachboiler)Limits: 120VAC,opticallyisolated


(eachboiler) DomesticHWPriority: 120VAC,opticallyisolatedOutputsModulation: Isolated4-20mADCor0-135ohm

(eachboiler)BoilerStart: Drycontact,8FLA,½HP,

120VAC(eachboiler)DomesticHWCirculationPump: Drycontact,8FLA,½HP,

120VAC

Ordering InformationSpecifyChiefDispatcherCatalogNumber:

JC-CDHW-2-PBoilerQuantity 2to10Analog Output Type 4-20mADC-I

0-135ohm-P

DOM. HW PRIORITY

FiringRateControlDialforModulatingOutputs


0-100%Bargraph

“On-Off-Auto”Switchesfor“On-Off”Outputs

“On-Off”InputswithStatusLEDs

DiagnosticsandCommunicationStatus

5 Boiler Controller Front Panel Shown



Catalog 25

Instruments &

Controls

133

1. ApplicationSupplyafullyintegratedboilercontrolsystemtocoordinatetheoperationoftwo(selectuptoten)fullymodulatinghotwaterboilersinordertomaintaintheHotWaterSupply(HWS)temperatureatsetpoint.Thecontrolsystemshallbemicroprocessor-basedandsuitableforwallmounting.2. Boiler ModulationThecontrolsystemshallincorporateaHWSheadertemperaturePIDcontrolscheme.Boilersshallbemodulatedin“Unison”(allatthesamefiringrate).Modulationsignalsshallbe4-20mADCor0-135ohm(asrequiredbytheboiler)andshallbeelectricallyisolatedchannel-channelandchannel-ground.3. Hot Water Supply (HWS) Temperature SetpointWhen theHWSTemperature control loop is in the “automatic”mode,thecontrolsystemshallestablishtheHWStemperaturesetpointbasedonthetimeofday,dayoftheweekandtheoutsideairtemperature.Whenin“manual”modetheoperatormaysettheHWStemperatureviaafrontpaneldisplay.Alltemperaturesandtime/datedatamustbefieldadjustablethrough“fill-in-the-blanks”styledisplays.Alternately,thecontrolsystemshallaccepta4-20mADCoutdoor air temperature reset setpoint signal fromanexternalBuildingAutomationSystem(BAS).4. Boiler SequenceThe control system shall utilize bothHWS temperature andboilerfiringratepercent tostartandstoptheboilersandshallminimizethetotalnumberofboilersinoperation.ThecontrollershallstartandstopboilerswhentheHWStemperatureisoutsidetheadjustable temperature limit for longer than theadjustabletimedelay.Inordertominimizeheadertemperaturedeviations,thecontrolsystemshallstartandstopthenextboilerwhenthe“lead”boilerisatanadjustablefiringratelimitforlongerthantheadjustabletimedelay.Thecontrolsystemshallmonitorbothboilerlockoutandlimitcircuitstoautomaticallyskipoverthoseboilersthat are powereddown formaintenance, trippedor otherwisewill not start.The lead boiler shall either automatically rotateonatimeofday,dayofweek(ormonth)schedule,orshallbemanuallyselectedbytheoperator.Theboilershallberunatlowfireforwarm-upforapresetlowfireholdtime.Thebaseloadramprateshallbefieldadjustable.TheControlSystemshallreducethefiringratetoaminimumbeforestoppingaboilertopreventaccumulationoffuelinthefurnace.

5. Operator Controls, Trends, Indications and AlarmsThe control system shall include a 16 line x 40 character (orgreater)LCDdisplayforboilersequencecontrolandstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,eventsandoperatoractionsshallbeloggedwithTime/DatestampandEnglishlanguagedescription..6. ReliabilityIncludehardwiredbackupstations topermitmanual operationoftheplantshouldthecontrolsystemrequireservice.Manualoperationmust be possiblewhen themicroprocessor is notfunctioning.Hardwired “Hand-Off-Auto” control switchesmustbewireddirectly intoeveryboilerandpumpStart/Stopcircuit.Each4-20mADCor0-135ohmmodulatingcontroloutputmustinclude a hardwiredmanual backup stationwithAuto/Manualswitch,outputcontrolknobandoutputlevelindicator(bargraph,analogmeterordigitaldisplay).7. CommunicationTheControl 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.8. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements(CSAC22.2#14foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).ThecontrolsystemshallbeaPreferredInstruments,Danbury,CT,Model JC-CDHW-x-P (‘x’=boilerquantityfrom2to10;“-P”for0-135ohm;“-I”for4-20mA).

CHIEF DISPATCHER MODEL JC-CDHWSuggestedSpecifications



Catalog 25

Inst

rum

ents

& C

ontro

ls

134

SystemReturn

SystemSupply

Boiler Start DO

DI BAS Disable All Boilers

Fuel Input DI

Typical for allBoiler

Typical for allPump

Headered PumpControl Option

AI Outside Air Temp

DI DHW Priority Command

AI Hot Water Supply Header Temp

DI Pump Flow Proven

RO Pump Start

TE

TE

FS FS

Alphanumeric Pager

PWC_Remote

Firing Rate AO

or Remote SP from BAS

CHIEF DISPATCHER MODEL JC-CDHWFCondensingHotWaterBoilersModulatingLead/LagController

ApplicationTheChiefDispatcherModel JC-CDHWF optimizeshotwatersystemperformanceandhelpsextendCastIronSectional,Finned-Tube,FireboxorFlexibleTubeboilerlife.

2 to 10 Fully Modulating BoilersHotWaterSupply(HWS)headertemperatureismaintainedusingaccuratePIDcontrol.Multipleboilersaremodulatedin“Unison”(allatthesamefiringrate)toensureevenheatisdeliveredevenly.Lagboilersarebroughtuptothe“unison”firing rateusingapredetermined ramp rate tomeet theheatingloadwithminimumovershoot.Whendesired,theoperatormaysetthe“unison”firingratemanually.

Outdoor ResetEnergyissavedbyloweringtheHotWaterSupply(HWS)temperature setpoint as the outside air temperatureincreases.Operatingcostisreducedduringwarmerdays.Whendesired, the operatormay set theHWSsetpointmanually.

Simplified DesignTheinstallationisreducedbymonitoringonlythefuelvalveinsteadofthenormallimitsandlockout.OutdoorresetorBASsetpointaswellashowmanyboilersareinstalledisfieldselectablewithoutreprogrammingtheunit.

JC-CDHWF, 2 to 10 Hot Water Boilers and optional header pump control



Catalog 25

Instruments &

Controls

135


Time of Day / Week SetbackThisfeatureisusedinheatingapplicationstosaveenergyby lowering theHotWaterSupply (HWS) temperaturesetpoint during timeswhen the heating requirement isreduced,suchasatnightoronweekendsandholidays.

Domestic Hot Water Priority (2 to 9 boiler systems) A temperature switch (thermostat) contact closure inputwilloverride the“outdoor reset”and“setbackportion”oftheprogramandforcetheHWStemperaturesetpointtoadomestichotwatersetpoint.Arelayoutputisavailabletostartadomestichotwaterpumpifrequired.

Condensing Boiler LogicCondensing boiler logic takes full advantage of thecondensing boiler design bymaximizing the number ofboilersrunningnearlowfiretoincreaseefficiency.

Header Pump ControlHeader circulating pumps are controlled to ensure acontinuous flow of water through the heating system.Pumpsarecontrolledforhandlingtheplant,andatrippedpumpisautomaticallyreplacedwithastandbyunit.Theleadpumpcanberotatedmanuallyorautomatically.



Catalog 25

Inst

rum

ents

& C

ontro

ls

136


JC-CDHWF-2-PCHBoilerQuantity 2to10Analog Output Type 4-20mADC-I

0-135ohm-P



CatalogNumber


Thermowell,SS,4½"x½"NPT 70610WOutsideAirThermistorTemperatureSensorwithweatherproofcover 70612


HeaderPumpControl JC-CDHWFxxx-H


InputsHotWaterTemperature: 0°to300°F,ThermistorOutdoorAirTemperature: ThermistorBASResetSetpoint: 4-20mADCBASBoilerDisable: 120VAC,opticallyisolated

(eachboiler)Fuel: 120VAC,opticallyisolated




120VAC

DOM. HW PRIORITY



0-100%Bargraph





CondensingHeaderPump



Catalog 25

Instruments &

Controls

137

CHIEF DISPATCHER MODEL JC-CDHWFSuggestedSpecifications

1. ApplicationSupplyafullyintegratedboilercontrolsystemtocoordinatetheoperationoftwo(selectuptoten)fullymodulating,condensinghotwaterboilersandheadersecondarywatercirculatingpumpsinordertomaintaintheHotWaterSupply(HWS)temperatureatsetpoint.Thecontrolsystemshallbemicroprocessor-basedandsuitableforwallmounting.2. Boiler ModulationThecontrolsystemshallincorporateaHWSheadertemperaturePIDcontrolscheme.Boilersshallbemodulatedin“Unison”(allatthesamefiringrate).Modulationsignalsshallbe4-20mADCor0-135ohm(asrequiredbytheboiler)andshallbeelectricallyisolatedchannel-channelandchannel-ground.3. Hot Water Supply (HWS) Temperature SetpointWhen theHWSTemperature control loop is in the “automatic”mode,thecontrolsystemshallestablishtheHWStemperaturesetpointbasedonthetimeofday,dayoftheweekandtheoutsideairtemperature.Whenin“manual”modetheoperatormaysettheHWStemperatureviaafrontpaneldisplay.Alltemperaturesandtime/datedatamustbefieldadjustablethrough“fill-in-the-blanks”styledisplays.Alternately,thecontrolsystemshallaccepta4-20mADCoutdoor air temperature reset setpoint signal fromanexternalBuildingAutomationSystem(BAS).4. Boiler SequenceThecontrolsystemshallusebothHWStemperatureandboilerfiring ratepercent tostartandstop theboilers,minimizing thetotalnumberofboilersinoperation.ThecontrollershallstartandstopboilerswhentheHWStemperatureisoutsidetheadjustabletemperature limit for longer than theadjustable timedelay.Tominimize header temperature deviations, the control systemshallstartandstop thenextboilerwhen the“lead”boiler isatanadjustablefiringratelimitforlongerthantheadjustabletimedelay.Thecontrolsystemshallmonitorboilerfuelvalvecircuitstoautomaticallyskipoverthoseboilersthatarepowereddownformaintenance,trippedorotherwisewillnotstart.Theleadboilershalleitherautomaticallyrotateonatimeofday,dayofweek(ormonth)schedule,orshallbemanuallyselectedbytheoperator.Theboilershallberunatlowfireforwarm-upforapresetlowfireholdtime.Thebaseloadramprateshallbefieldadjustable.Thecontrolsystemshallreducethefiringratetoaminimumbeforestoppingaboilertopreventaccumulationoffuelinthefurnace.

5. Operator Controls, Trends, Indications and AlarmsThe control system shall include a 16 line x 40 character (orgreater)LCDdisplayforboilersequencecontrolandstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,events,andoperatoractionsshallbeloggedwithTime/DatestampandEnglishlanguagedescription..6. ReliabilityIncludehardwiredbackupstationstopermitmanualoperationoftheplantifthecontrolsystemrequireservice.Manualoperationmust be possiblewhen themicroprocessor is not functioning.Hardwired“Hand-Off-Auto”controlswitchesmustbewireddirectlyintoeveryboilerandpumpStart/Stopcircuit.Each4-20mADCor0-135ohmmodulatingcontroloutputmustincludeahardwiredmanualbackupstationwithAuto/Manualswitch,outputcontrolknobandoutputlevelindicator(bargraph,analogmeterordigitaldisplay).7. CommunicationTheControl System shall have the ability of simultaneouslycommunicating to aDataAcquisitionSystem (DAS),BuildingAutomation System (BAS) or BuildingManagement System(BMS)viaRS485ModbusprotocolandtoaPersonalComputer.Theindividualboilerlimits,lockout,start/stop,warmstandby,andfiringratestatusshallberead.Headersetpoint,plantfiringrate,boilerquantitycalledtostart,boilerselectedasleadandallsetupparametersshallbereadableandwritable.8. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements (CSAC22.2#14 foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).ThecontrolsystemshallbeaPreferredInstruments,Danbury,CT,Model JC-CDHWF-C-H-x-P (‘x’=boilerquantityfrom2to10;“-P”for0-135ohm;“-I”for4-20mA).



Catalog 25

Inst

rum

ents

& C

ontro

ls

138

CHIEF DISPATCHER MODEL JC-CDHWBPHotWaterBoilerswithBoilerPumpsModulatingLead/LagController

ApplicationTheChiefDispatcherModelJC-CDHWBPoptimizeshotwater systemperformanceand helps extendCast IronSectional,Finned-Tube,FireboxorFlexibleTubeboilerlife.Boiler pump sequencing ensures accurate temperaturesensing,andboilercooldown.

2 to 7 Fully Modulating BoilersHotWaterSupply(HWS)headertemperatureismaintainedusingaccuratePIDcontrol.Multipleboilersaremodulatedin“Unison”(allatthesamefiringrate)toensureevenheatdelivery.Lagboilersarebroughtuptothe“Unison”firingrateusingapredeterminedRampRatetomeettheheatingloadwithminimumovershoot.Theoperatormayset the“Unison”firingratemanually.

Boiler Pump Sequencing Inline,boilerpumpsequencingkeepstheleadboilerpumprunning(thereforewaterflowingpasttheheadersensor)toensureaccurateheadertemperaturesensingandprovidespumpshutdowndelayforboilercooldown.Dedicatedboileroutletvalves(relayoutputtoopen)canbecontrolledinsteadofdedicatedboilerpump.


JC-CDHWBP2 to 7 Hot Water Boilers and Primary Loop Pumps

Outdoor ResetEnergy is saved by decreasing theHotWater Supply(HWS)temperaturesetpointastheoutsideairtemperatureincreases.Operatingcostisreducedduringwarmerdays.TheoperatormaysettheHWSsetpointmanually.

Time of Day / Week SetbackThisfeatureisusedinheatingapplicationstosaveenergyby lowering theHotWaterSupply (HWS) temperaturesetpoint during timeswhen the heating requirement isreduced,suchasnights,weekends,andholidays.

Domestic Hot Water Priority A temperature switch (thermostat) contact closure inputwill override theOutdoorReset andSetback portion oftheprogramandforcetheHWStemperaturesetpointtoaDomesticHotWaterSetpoint.Arelayoutputisavailabletostartadomestichotwaterpumpifrequired.

Condensing Boiler Logic (option “-C”)Condensingboilerlogicusesthecondensingboilerdesigntomaximizethenumberofboilersrunningnearlowfiretomaximizeefficiency.



Catalog 25

Instruments &

Controls

139

DOM. HW PRIORITY



0-100%Bargraph






CatalogNumber


Thermowell,SS,4½"x½"NPT 70610WOutsideAirThermistorTemperatureSensorwithweatherproofcover 70612


BuildingAutomationSystem(BAS)4-20mADCSetpoint add“-BAS”suffix

CondensingBoilerLogic add“-C”suffix

CHIEF DISPATCHER MODEL JC-CDHWBPHotWaterBoilerswithBoilerPumpsModulatingLead/LagController


InputsHotWaterTemperature: 0ºto300°F,ThermistorOutdoorAirTemperature: Thermistor(non“BAS”version)BASResetSetpoint: 4-20mADC(“-BAS”version)BASBoilerDisable: 120VAC,opticallyisolated

(eachboiler)Limits: 120VAC,opticallyisolated




120VAC(eachboiler)PumpStart: Drycontact,8FLA,½HP,


120VAC


JC-CDHWBP-2-PBoilerQuantity 2to7Analog Output Type 4-20mADC-I

0-135ohm-P



Catalog 25

Inst

rum

ents

& C

ontro

ls

140

1. ApplicationSupplyafullyintegratedboilercontrolsystemtocoordinatetheoperationoftwo(selectuptoseven)fullymodulatinghotwaterboilers andboiler primarywater circulatingpumps in order tomaintain theHotWaterSupply(HWS)temperatureatsetpoint.Thecontrolsystemshallbemicroprocessor-basedandsuitableforwallmounting.2. Boiler ModulationThecontrolsystemshallincorporateaHWSheadertemperaturePIDcontrolscheme.Boilersshallbemodulatedin“Unison”(allatthesamefiringrate).Modulationsignalsshallbe4-20mADCor0-135ohm(asrequiredbytheboiler)andshallbeelectricallyisolatedchannel-channelandchannel-ground.3. Hot Water Supply (HWS) Temperature SetpointWhen theHWSTemperature control loop is in the “automatic”mode,thecontrolsystemshallestablishtheHWStemperaturesetpointbasedonthetimeofday,dayoftheweekandtheoutsideairtemperature.Whenin“manual”modetheoperatormaysettheHWStemperatureviaafrontpaneldisplay.Alltemperaturesandtime/datedatamustbefieldadjustablethrough“fill-in-the-blanks”styledisplays.Alternately,thecontrolsystemshallaccepta4-20mADCoutdoor air temperature reset setpoint signal fromanexternalBuildingAutomationSystem(BAS).4. Boiler SequenceThe control system shall utilize bothHWS temperature andboilerfiringratepercent tostartandstoptheboilersandshallminimizethetotalnumberofboilersinoperation.ThecontrollershallstartandstopboilerswhentheHWStemperatureisoutsidetheadjustable temperature limit for longer than theadjustabletimedelay.Inordertominimizeheadertemperaturedeviations,thecontrolsystemshallstartandstopthenextboilerwhenthe“lead”boilerisatanadjustablefiringratelimitforlongerthantheadjustabletimedelay.Thecontrolsystemshallmonitorbothboilerlockoutandlimitcircuitstoautomaticallyskipoverthoseboilersthatarepowereddownformaintenance,trippedorotherwisewillnotstart.Theleadboilershalleitherautomaticallyrotateonatimeofday,dayofweek(ormonth)schedule,orshallbemanuallyselectedbytheoperator.Theboilershallberunat lowfireforwarm-upforapresetlowfireholdtime.Thebaseloadramprateshallbefieldadjustable.Thecontrolsystemshallreducethefiringratetoaminimumbeforestoppingaboilertopreventaccumulationoffuelinthefurnace.5. Boiler Pump SequenceInclude independentlyoperatedprimarywaterpumpcontrol toallowboilerwarm-uptothereturnwatertemperaturebeforetheboilers start, continuewater flow for an adjustable cool downperiodaftertheboilerhasstopped,andensurewaterisalwaysmovingpasttheheadertemperaturesensorevenafterthelastboilerhasbeenstopped.Thepumpshallimmediatelystopifanytripsoccurduringpre-purge,pilot,ormainflametrialforignition.

6. Operator Controls, Trends, Indications and AlarmsThe control system shall include a 16 line x 40 character (orgreater)LCDdisplayforboilersequencecontrolandstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,eventsandoperatoractionsshallbeloggedwithtime/datestampandEnglishlanguagedescription..7. ReliabilityIncludehardwiredbackupstations topermitmanual operationof theplantshould thecontrolsystemrequireservice.Manualoperationmust be possiblewhen themicroprocessor is notfunctioning.Hardwired“hand-off-auto”controlswitchesmustbewireddirectlyintoeveryboilerandpumpstart/stopcircuit.Each4-20mADCor0-135ohmmodulatingcontroloutputmustincludeahardwiredmanualbackupstationwithauto/manualswitch,outputcontrolknobandoutputlevelindicator(bargraph,analogmeterordigitaldisplay).8. 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,boilerselectedasleadandallsetupparametersshallbereadableandwritable.9. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements (CSAC22.2#14 foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).Thecontrol systemshall beaPreferred Instruments,Danbury,CT,Model JC-CDHWBP-x-P (‘x’=boilerquantityfrom2to7;“-P”for0-135ohm;“-I”for4-20mA).

CHIEF DISPATCHER MODEL JC-CDHWBPSuggestedSpecifications



Catalog 25

Instruments &

Controls

141

ApplicationTheChiefDispatcherModel JC-CDHWHP optimizeshotwatersystemperformance,andhelpsextendCastIronSectional,Finned-Tube,FireBoxorFlexibleTubeboilerlife.Headerpumpsequencingensuresaccuratetemperaturesensingandafailedpumpisreplacedwithabackuppump.

2 To 5 Modulating BoilersHotWaterSupply(HWS)headertemperatureismaintainedusingaccuratePIDcontrol.Multipleboilersaremodulatedin“unison”(allatthesamefiringrate)toensureevenheatdelivery.Lagboilersarebroughtuptothe“unison”firingrateusingapredeterminedrampratetomeettheheatingloadwithminimumovershoot.Whendesired,theoperatormaysetthe“unison”firingratemanually.

Header Pump Sequencing Header pump sequencing keeps the lead boiler pumprunning(thereforewaterflowingpasttheheadersensor)toensureaccurateheadertemperaturesensingandprovidespumpshutdowndelayforboilercooldown.Additionally,afailedpumpisautomaticallyreplacedwithabackup.

AI HOT WATER SUPPLY HEADER TEMP

OUTSIDE AIR TEMPERATURE

OR REMOTE SETPOINT FROM BAS

JC-CDHWHP2 to 5 Hot Water Boilers and Headered Primary Loop Pumps

Outdoor Reset EnergyissavedbyloweringtheHotWaterSupply(HWS)temperature setpoint as the outside air temperatureincreases.Operatingcostisreducedduringwarmerdays.Whendesired, the operatormay set theHWSsetpointmanually.

Time Of Day / Week Setback Thisfeatureisusedinheatingapplicationstosaveenergyby lowering theHotWaterSupply (HWS) temperaturesetpoint during timeswhen the heating requirement isreduced,suchasatnights,weekends,andholidays.

Domestic Hot Water PriorityA temperature switch (thermostat) contact closure inputwilloverride the“outdoor reset”and“setback”portionoftheprogramandforcetheHWStemperaturesetpointtoa“domestichotwatersetpoint.”Arelayoutputisavailabletostartadomestichotwaterpumpifrequired.

Condensing Boiler Logic (Option “-C”)Condensing boiler logic takes full advantage of thecondensing boiler design bymaximizing the number ofboilersrunningnearlowfiretomaximizeefficiency.

CHIEF DISPATCHER MODEL JC-CDHWHPHotWaterBoilerswithHeaderPumpsModulatingLead/LagController



Catalog 25

Inst

rum

ents

& C

ontro

ls

142


InputsHotWaterHeader: 0ºto300°F,ThermistorOutdoorAir: Thermistor(non“-BAS”version)BASResetSetpoint: 4-20mADC(“-BAS”version)BASBoilerDisable: 120VAC,opticallyisolatedLimits: 120VAC,opticallyisolated


(eachboiler)PumpFlowProven: 120VAC,opticallyisolated


(eachboiler)BoilerStart: DryContact,8FLA,½HP,120VAC

(eachboiler)PumpStart: DryContact,8FLA,½HP,120VAC

(eachboiler)ValveOpen: DryContact,8FLA,½HP,120VAC

(eachboiler)DomesticHWCirculationPump: DryContact,8FLA,½HP,120VAC

CHIEF DISPATCHER MODEL JC-CDHWHPHotWaterBoilerswithHeaderPumpsModulatingLead/LagController

OPEN - CLOSE - AUTO

OPEN - CLOSE - AUTO

OPEN - CLOSE - AUTO

OPEN - CLOSE - AUTO

OPEN - CLOSE - AUTODOM. HW PRIORITY

DOM. HW CIRC.



0-100%Bargraph


“On-Off”Inputswith StatusLEDs

5 Boiler Controller Front Panel

Diagnosticsand CommunicationStatus


CatalogNumber


Thermowell,SS,4.5"x½NPT 70610WOutsideAirThermistorTemperatureSensorwithweatherproofcover 70612





JC-CDHWHP-2-P-2BoilerQuantity 2to5Analog Output Type 4-20mADC-I

0-135ohm-P

HeaderPumpQuantity 2to3



Catalog 25

Instruments &

Controls

143

1. ApplicationSupplyafullyintegratedboilercontrolsystemtocoordinatetheoperationof two (select up to five) fullymodulatinghotwaterboilers,two(selectuptothree)headerprimarywatercirculatingpumpsandboilerwaterflowcontrolvalvesinordertomaintaintheHotWaterSupply(HWS)temperatureatsetpoint.Thecontrolsystem shall bemicroprocessor-based and suitable forwallmounting.2. Boiler ModulationThecontrolsystemshallincorporateaHWSheadertemperaturePIDcontrolscheme.Boilersshallbemodulatedin“unison”(allatthesamefiringrate).Modulationsignalsshallbe4-20mADCor0-135ohm(asrequiredbytheboiler)andshallbeelectricallyisolatedchannel-channelandchannel-ground.3. Hot Water Supply (HWS) Temperature SetpointWhen theHWSTemperature control loop is in the “automatic”mode,thecontrolsystemshallestablishtheHWStemperaturesetpointbasedonthetimeofday,dayoftheweekandtheoutsideairtemperature.Whenin“manual”modetheoperatormaysettheHWStemperatureviaafrontpaneldisplay.Alltemperaturesandtime/datedatamustbefieldadjustablethrough“fill-in-the-blanks”styledisplays.Alternately,thecontrolsystemshallaccepta4-20mADCoutdoor air temperature reset setpoint signal fromanexternalBuildingAutomationSystem(BAS).4. Boiler SequenceThe control system shall utilize bothHWS temperature andboilerfiringratepercent tostartandstoptheboilersandshallminimizethetotalnumberofboilersinoperation.ThecontrollershallstartandstopboilerswhentheHWStemperatureisoutsidetheadjustable temperature limit for longer than theadjustabletimedelay.Inordertominimizeheadertemperaturedeviationsthecontrolsystemshallstartandstopthenextboilerwhenthe“lead”boilerisatanadjustablefiringratelimitforlongerthantheadjustabletimedelay.Thecontrolsystemshallmonitorbothboilerlockoutandlimitcircuitstoautomaticallyskipoverthoseboilersthatarepowereddownformaintenance,trippedorotherwisewillnotstart.Theleadboilershalleitherautomaticallyrotateonatimeofday,dayofweek(ormonth)schedule,orshallbemanuallyselectedbytheoperator.Theboilershallberunat lowfireforwarm-upforapresetlowfireholdtime.Thebaseloadramprateshallbefieldadjustable.Thecontrolsystemshallreducethefiringratetoaminimumbeforestoppingaboilertopreventaccumulationoffuelinthefurnace.5. Header Pump SequenceProvidemainheaderprimarywaterpumpcontroltoimprovefiredequipment availability. Start the quantity of header pumps asrequiredforthenumberofboilersinoperation.Thecontrolsystemshallmonitorpumpoutletflowswitchstatustoautomaticallystartastandbypumpwhenacommandtostartthepumpfailstoproduceflow.Systemmustkeepatleastonepumprunningtoensurewaterisalwaysmovingpasttheheadertemperaturesensorevenafterthelastboilerhasbeenstopped.

6. Boiler Water Flow Control Valve SequenceProvideboilerwaterflowvalvecontroltopreventwaterfromflowingthrough off-line boilers (and lowering theHWS temperature);continuewaterflowforanadjustablecooldownperiodaftertheboilerhasstopped,andensurewaterisalwaysmovingpasttheheadertemperaturesensorevenafterthelastboilerhasbeenstopped.Thevalveshallbeimmediatelyclosedifanytripsoccurduringpre-purge,pilot,ormainflametrialforignition.7. Operator Controls, Trends, Indications and AlarmsThe control system shall include a 16 line x 40 character (orgreater)LCDdisplayforboilersequencecontrolandstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,eventsandoperatoractionsshallbeloggedwithtime/datestampandEnglishlanguagedescription.8. ReliabilityIncludehardwiredbackupstations topermitmanual operationof theplantshould thecontrolsystemrequireservice.Manualoperationmust be possiblewhen themicroprocessor is notfunctioning.Hardwired“Hand-Off-Auto”controlswitchesmustbewireddirectlyintoeveryboiler,pump,andvalvestart/stopcircuit.Each4-20mADCor0-135ohmmodulatingcontroloutputmustinclude a hardwiredmanual backup stationwith auto/manualswitch,outputcontrolknobandoutputlevelindicator(bargraph,analogmeterordigitaldisplay).9. 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.10. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements (CSAC22.2#14 foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).Thecontrol systemshall beaPreferred Instruments,Danbury,CT,Model JC-CDHWHP-x-P-y (“x”=boilerquantityfrom2to5;“-P”for0-135ohm;“-I”for4-20mA;“y”=pumpquantityfrom2to3).

CHIEF DISPATCHER MODEL JC-CDHWHPSuggestedSpecifications



Catalog 25

Inst

rum

ents

& C

ontro

ls

144

CHIEF DISPATCHER MODEL JC-CDHWTSPHotWaterBoilerswithThermalShockProtectionModulatingLead/LagController

ApplicationTheChiefDispatcherModel JC-CDHWTSP willoptimizehotwater system performance and help extend boiler life.Blendvalvesareusedtoallowoff-lineboilerwarm-upandpreventthermalshock.2 To 4 Modulating BoilersHotWaterSupply(HWS)headertemperatureismaintainedusingaccuratePIDcontrol.Multipleboilersaremodulatedin“unison”(allatthesamefiringrate)toensureevenheatdelivery.Lagboilersarebroughtuptothe“unison”firingrateusingapredeterminedrampratetomeettheheatingloadwithminimumovershoot.Theoperatormaysetthe“unison”firingratemanually.Eachboilerhasanindividualboileroutlettemperaturesensor.Ifanyboilerapproachesitshightemperatureshutdownlimit, itwillcutbackfiringrateindividuallytopreventaboilertrip.Boiler Pump Sequencing Inlineboilerpumpsequencingkeepstheleadboilerpumprunning (water flowspast theheader sensor) to ensureaccurateheadertemperaturesensingandprovidespumpshutdowndelayforboilercooldown.Thermal Shock ProtectionIndividual boiler outlet 3-way recirculating valves areautomaticallypositionedbasedontheboilerstartsequence,boiler outlet and returnwater temperatures. If theboilerreturnwater temperaturedropsbelowa lowtemperaturesetpoint,thevalveopenstoallowhotboileroutletwaterto


OUTSIDE AIR TEMPERATURE

OR REMOTE SETPOINT FROM BAS

JC-CDHWTSP2 to 4 Hot Water Boilers, Primary Loop Pumps and Blend Valves

blendwithcoldreturnwatertemperature.Thevalveslowlyrepositionstoward0%recirculationafterreturnwaterrisesabovesetpoint.Whenaboileriscalledtooperate,the3-wayvalveissetto95%recirculation.Aftertheboilerstartsandtheoutlettemperatureisclosetosupplytemperaturesetpoint,thevalveslowlyrepositionstoward0%recirculation.Outdoor Reset EnergyissavedbyloweringtheHotWaterSupply(HWS)temperature setpoint as the outside air temperatureincreases.Operatingcostisreducedduringwarmerdays.TheoperatormaysettheHWSsetpointmanually.Time Of Day/ Week Setback Thisfeatureisusedinheatingapplicationstosaveenergyby lowering theHotWaterSupply (HWS) temperaturesetpoint during timeswhen the heating requirement isreduced,suchasatnightoronweekendsandholidays.Domestic Hot Water PriorityA temperature switch (thermostat) contact closure inputwilloverride the“outdoor reset”and“setback”portionoftheprogramandforcetheHWStemperaturesetpointtoadomestichotwatersetpoint.Arelayoutputisavailabletostartadomestichotwaterpumpifrequired.Condensing Boiler Logic (Option “-C”)Condensing boiler logic takes full advantage of thecondensing boiler design bymaximizing the number ofboilersrunningnearlowfiretomaximizeefficiency.



Catalog 25

Instruments &

Controls

145

DOM. HW PRIORITY

DOM. HW PRIORITY



0-100%Bargraph



4 Boiler Controller Front Panel


CatalogNumber

HotWaterThermistorTemp.Sensor0ºto300ºF,4½"depth 70610

Thermowell,SS,4½"x½NPT 70610WOutsideAirThermistorTemp.Sensorwithweatherproofcover 70612


AnalogInputswithStatusIndicator

CHIEF DISPATCHER MODEL JC-CDHWTSPHotWaterBoilerswithThermalShockProtectionModulatingLead/LagController




SpecificationsPanel DetailsController: PWCCaseSize: 19¼"HX18"WX8½"D

EnclosureType: Wallmounted,Weight:55lbs.InputsHotWaterTemperature: 0ºto300°F,ThermistorOutletWater: Thermistor(eachboiler)ReturnWater: Thermistor(eachboiler)OutdoorAir: Thermistor(non“-BAS”version)BASResetSetpoint: 4-20mADC(“-BAS”version)BAS,BoilerDisable: 120VAC,opticallyisolatedLimits: 120VAC,opticallyisolated(eachboiler)BoilerLockout: 120VAC,opticallyisolated(eachboiler)

DomesticHWPriority: 120VAC,opticallyisolatedOutputsBoilerModulation: Isolated:4-20mADCor0-135ohm

(eachboiler)BalancingValve: Isolated:4-20mADC

(eachboiler)BoilerStart: Drycontact,8FLA,½HP,120VAC

(eachboiler)PumpStart: Drycontact,8FLA,½HP,120VAC

(eachboiler)DomesticHWCirculationPump: Drycontact,8FLA,½HP,120VAC


JC-CDHWTSP-2-PBoilerQuantity 2to4Analog Output Type 4-20mADC-I

0-135ohm-P



Catalog 25

Inst

rum

ents

& C

ontro

ls

146

1. Application Supplyafullyintegratedboilerhotwatercontrolsystemtocoordinatetheoperationoftwo(selectuptofour)fullymodulatinghotwaterboilers,boilerwatercirculatingpumpsandboilerwaterflowcontrolvalvestomaintainHotWaterSupply(HWS)temperatureatsetpointandprovidethermalshockprotection.Thecontrolsystemshallbemicroprocessor-basedandsuitableforwallmounting.2. Boiler ModulationThecontrolsystemshallincorporatea“cascadewithcutback”HWStemperaturePIDcontrolscheme.TheHWStemperatureshallbecomparedwithasetpoint toestablisha targetboilerfiring rate. Ifanindividualboileroutlettemperatureexceedsapre-setmaximumsetpoint,thatboiler’sfiringrateshallbeautomaticallycutbackbyaPIDlooptopreventahightemperaturetrip.Boilersshallbemodulatedin“unison”(allatthesamefiringrate).Modulationsignalsshallbe4-20mADCor0-135ohm(asrequiredbytheboiler)andshallbeelectricallyisolatedchannel-channelandchannel-ground.3. Hot Water Supply (HWS) Temperature SetpointWhentheHWSTemperaturecontrolloopisinthe“automatic”mode,thecontrolsystemshallestablishtheHWStemperaturesetpointbasedonthetimeofday,dayoftheweekandtheoutsideairtemperature.Whenin“manual”modetheoperatormaysettheHWStemperatureviaafrontpaneldisplay.Alltemperaturesandtime/datedatamustbefieldadjustablethrough“fill-in-the-blanks”styledisplays.Alternately,thecontrolsystemshallaccepta4-20mADCoutdoorairtemperatureresetsetpointsignalfromanexternalBuildingAutomationSystem(BAS).4. Boiler SequenceThecontrolsystemshallusebothHWStemperatureandboilerfiringratepercenttostartandstoptheboilers,minimizingthetotalnumberofboilersinoperation.ThecontrollershallstartandstopboilerswhentheHWStemperatureisoutsidetheadjustabletemperaturelimitforlongerthantheadjustabletimedelay.Inordertominimizeheadertemperaturedeviations,thecontrolsystemshallstartandstopthenextboilerwhenthe“lead”boilerisatanadjustablefiringratelimitfor longerthantheadjustabletimedelay.Thecontrolsystemshallmonitorbothboilerlockoutandlimitcircuitstoautomaticallyskipoverboilersthatarepowereddownformaintenance,trippedorotherwisewillnotstart.Theleadboilershalleitherautomaticallyrotateonatimeofday,dayofweek(ormonth)schedule,orshallbemanuallyselectedbytheoperator.Theboilershallberunatlowfireforwarm-upforapresetlowfireholdtime.Thecontrolsystemshallreducethefiringratetoaminimumbeforestoppingaboilertopreventaccumulationoffuelinthefurnace.5. Boiler Pump SequenceIncludeindependentlyoperatedprimarywaterpumpcontrol.Systemmustkeepatleastonepumprunningtoensurewaterisalwaysmovingpasttheheadertemperaturesensor.6. Boiler Water Flow Control Valve SequenceProvidecontrolforanelectricactuator,wtihslowopening(2minute),flowbalancing,twovalveassemblyforeachboiler.Thevalveassemblyshalllinkaboileroutletvalveandboilerwaterrecirculationvalvesothattheyoperateasasingleunit.Thevalvesshallbearrangedsothatasonevalvecloses,theothervalveopens,ensuringacontinuous

flowofwaterthroughtheboiler.Theassemblyshallacceptasingle4-20mADCsignaltopositionbothvalves.Thisvalveshallpreventwater fromflowing throughoff-lineboilers (and lowering theHWStemperature), allowboilerwarm-up to returnwater temperaturebefore theboilerstarts,continuewaterflowforanadjustablecooldownperiodaftertheboilerhasstopped,andensurewaterisalwaysmovingpasttheheadertemperaturesensorevenafterthelastboilerhasbeenstopped.Slowlyjogopenthevalveovera10-minuteperiod(adjustable) topreventboiler thermalshocking. If theboiler returnwatertemperatureis50°F(adjustable)belowtheboileroutletwatertemperature,thevalveshallslowlyjogclosed,causingboileroutletwatertoblendwiththeexcessivelycoldreturnwater.Whenthereturnwatertemperaturereturnstoanacceptablerange,theboileroutletvalveshallslowlyjogopen.7. Operator Controls, Trends, Indications and AlarmsThecontrolsystemshallincludean16linex40character(orgreater)LCDdisplay forboiler sequencecontrol andstatus,alarmandeventsummaries,andsetupmenusforeasyoperation,tuningandtroubleshooting.Alarms,eventsandoperatoractionsshallbeloggedwithtime/datestampandEnglishlanguagedescription.8. ReliabilityIncludehardwiredbackupstationstopermitmanualoperationoftheplantshouldthecontrolsystemrequireservice.Manualoperationmustbepossiblewhenthemicroprocessorisnotfunctioning.Hardwired“hand-off-auto”control switchesmustbewireddirectly intoeveryboilerandpumpstart/stopcircuit.Each4-20mADCor0-135ohmmodulatingcontroloutputmustincludeahardwiredmanualbackupstationwithauto/manualswitch,outputcontrolknobandoutputlevelindicator(bargraph,analogmeterordigitaldisplay).9. 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,boilerselectedasleadandallsetupparametersshallbereadableandwritable.10. Quality AssuranceThe control system shall bemanufactured and labeled inaccordancewithUL508requirements (CSAC22.2#14 foruseinCanada).InspectionandlabelingshallbesupervisedbyULorotherOSHAapprovedNationallyRecognizedTestLab(NRTL).Thecontrol systemshall beaPreferred Instruments,Danbury,CT,Model JC-CDHWTSP-x-P (‘x’=boilerquantityfrom2to4;“-P”for0-135ohm;“-I”for4-20mADC).

CHIEF DISPATCHER MODEL JC-CDHWTSPSuggestedSpecifications

chief dispatcher modulating lead/lag controllers … · chief dispatcher modulating lead/lag...

Documents