Steffes DLF30B User manual

DLF4
OWNER'SAND
INSTALLER'SMANUAL
for
DoubleLoop(Central)Furnaces
"Manufactured in North America" 
U.S. Pat. #5201024
Can. Pat. #2060881
Models:DLF30B&DLF40B

General Information
GeneralOperation .................................................................................................................................................................... 2
Terminology............................................................................................................................................................................ 3
Safety Information
SafetyPrecautions ................................................................................................................................................................... 4
BuiltinSafetyDevices............................................................................................................................................................ 4
Maintenance and Cleaning........................................................................................................ 4
Furnace Control Panel................................................................................................................... 56
Operating the Furnace
FurnaceStartup ...................................................................................................................................................................... 7
RoomTemperatureControl...................................................................................................................................................... 7
BrickTemperatureControl(CoreCharging)........................................................................................................................... 78
HowtoTurntheFurnace"OFF"and"ON".............................................................................................................................. 8
Installing the Furnace
Shipping................................................................................................................................................................................. 9
Placement ................................................................................................................................................................................ 9
ClearanceRequirements ......................................................................................................................................................... 10
FurnaceSetup..................................................................................................................................................................1012
BrickLoading....................................................................................................................................................................1213
InstallingtheHeatingElements .............................................................................................................................................. 13
Ducting .............................................................................................................................................................................1314
LineVoltageElectricalConnections ...................................................................................................................................1518
LowVoltageElectricalConnections...................................................................................................................................1922
FurnaceFinalTestProcedure ................................................................................................................................................. 23
Furnace Specifications................................................................................................................... 24
Exploded View Parts Diagram ............................................................................................... 25
Furnace Parts List...............................................................................................................................2627
Troubleshooting Information
BrickCoreTemperatureTesting............................................................................................................................................. 28
TroubleshootingGuides....................................................................................................................................................2934
Warranty
Table of Contents
1

• ThismanualprovidesinformationforcorrectinstallationproceduresandelectricalconnectionsforSteffesETS
DoubleLoopFurnaces,ModelsDLF30BandDLF40B.Theinformationinthismanualwillhelpyouutilizethe
product'smanyfeaturesandensuremanyyearsofsafe,reliableoperation.Readalltheinformationcontained
withinthismanualbeforeinstallingthesystem.Storethismanualinasafeplaceforfuturereference.
• Assemblyofand/orservicetotheseunitsshouldbeperformedonlybyaqualifiedelectricianinaccordancewith
informationcontainedhereinandinaccordancewithnational,state,andlocalelectricalcodes.
• Thismanualmustberetainedbynewownersifownershipofthefurnacechanges.
• Anydeviationfromtheseinstructionsmayvoidthewarrantyandcouldresultinhazardousoperatingconditions.
• Thewarrantyregistrationcardprovidedaspartoftheunitdocumentationsetmustbecompletedandreturnedto
SteffesCorporation.Failuretodosomayadverselyaffectwarrantyclaims.
• Recordtheserialnumberandmodelnumberinthespacesprovidedonthebackpageofthismanual.These
numbersarelocatedontherightsideofthefurnacebase,ontheshippingbox,andonthewarrantyregistration
card.Retainthismanualforaquickreferencetothesenumbers.
• DISCLAIMER: Incompilingthismanual,SteffesCorporationhasuseditsbestjudgementbaseduponinfor
mationavailablebutdisclaimsanyresponsibilityorliabilityforanyerrorsormiscalculationscontainedherein,or
anyrevisionshereof,orwhichresult,wholeorinpart,fromtheuseofthismanualoranyrevisionshereof.
2 General Information
GENERAL OPERATION
TheSteffesETSDoubleLoopCentralFurnace(DLF)utilizesoffpeakelectricitywhichisavailableduring
timesofthedayornightwhenthepowercompanycansupplyelectricitymoreeconomically.Byusingthisoff
peakelectricityforheating,thepowercompanymayofferaspecialincentivesuchasareducedelectricrate,
anoffpeakheatingrate,atimeofuse(TOU)rate,ormonthlycreditsonyourheatingbill.
Whenoffpeakhoursareavailable,thefurnaceconvertselectricitytoheatwhichisthenstoredinitsceramic
brickcore.Theamountofheatstoredinthebrickcorevariesinrelationtooutdoortemperature,owner
preference,utilitypeakconditions,andtherequirementsofthespacebeingheated.Thisstoredheatbecomes
availableforspaceheatingneedsasdeterminedbythewallthermostatthatisstrategicallylocatedintheliving
space.
Whenthewallthermostatsensesaneedforheat,thecoreblowerandsupplyblowerinthefurnaceoperate.
Thecoreblowercirculatesthehotbrickairandwarmstheheatexchangerlocatedinthebaseofthefurnace.
Thesupplyairblowercirculatesroomairthroughtheexchangerwhereitisheatedandthendeliversittothe
conditionedspace.
1

Automatic Charge Control Methodofbrickcorechargeregulationwhereasensormonitorsoutdoor
temperaturetoautomaticallyadjustthebrickcoretemperaturesettinginrelation
totheoutdoortemperature.
Brick Core Charge Level Theamountofheatthatisstoredintheheater’sbrickcore.
Charge Period Offpeaktimeinwhichthefurnaceisallowedtostoreheatinitsbrickcore.
Control Panel Containsthetoggleswitchestoadjustanddisplaylightstoindicatefurnace
operation.Locatedonthelowerfrontofthefurnaceontheelectricalpanel.
Control Period Onpeaktimeinwhichthefurnaceisnotallowedtostoreheatinitsbrickcore.
Heat Call Whenroomtemperaturefallsbelowtheroom’sthermostatsetting,thethermo
statsignalsthefurnacetooperateitsblowersanddeliverwarmairintothe
spacetoraisethetemperaturetothedesiredthermostatsetpoint.
Heat Exchanger Deviceinthebaseofthefurnacewherethestoredheatfromthebrickcore
transferstotheductsystemfordeliveryintothelivingspace.
Manual Charge Control Methodofbrickcorechargingregulationwheretheusermustperiodicallyadjust
thebrickcoretemperaturesettinginrelationtotheoutdoortemperature.
OffPeak Thetimeduringthedayornightwhenthepowercompanycansupplyelectricity
moreeconomicallyandmayofferaspecialincentivesuchasareducedelectric
rateorbillingcreditsfortheelectricityconsumedduringthistime.Typically,
uncontrollableelectricalusageisallowedduringthistime.(Furnaceisallowed
tochargeorstoreheatinitsbrickcoreduringthistime.)
OnPeak Thetimeduringthedayornightwhenthepowercompanyexperiencesahigh
demandforelectricity.Tolimitdemand,certainappliancesarecontrolledto
avoidusagebythemand/orapremiumfortheelectricityconsumedduringthis
timemaybecharged.(Furnaceisnotallowedtochargeorstoreheatinits
brickcoreduringthistime.)
Outdoor Temperature Sensor Devicethatsensesoutdoorairtemperatureandcommunicatesthisinformation
tothefurnaceforautomaticchargecontrol.
Peak Override Enableselectricalusageinadevicethatistypicallycontrolledbythepower
companyduringanonpeaktime.Somepowercompaniesmayneverpermit
anycontrolleddevicestobeusedduringanonpeaktime.Othersthatdomay
penalizetheuserbychargingapremiumonenergyconsumedduringthisperiod.
3
General Information (cont'd)
TERM DEFINITION
TERMINOLOGY
Thismanualcontainstermswhichmayneedexplanation.Thetablebelowlistssomeofthesetermsandabrief
descriptionofeach.
2

DEVICENAME FUNCTION
Safety Information
LOCATION
ON HEATER
SAFETY PRECAUTIONS
1. DONOTenergizethefurnacewhiledisassembledorwithoutceramicheatstoragebrickinplace.
2. Asistruewithallheatingappliances,materialsthatmayproduceexplosiveorflammablegasesMUSTNOT
beusedorstorednearthefurnace.
3. Besuretheminimumclearancerequirementsspecifiedinthismanualareneverviolated.
4. Thisunitmaybeconnectedtomorethanonebranchcircuit.Disconnectpowertoallcircuitsbeforeservicing.
BUILT-IN SAFETY DEVICES
AllSteffesDoubleLoopCentralFurnacesincorporatesafetydevicestoensurenormaloperatingtemperatures
aremaintained.The chart belowdescribesthesesafetydevices.
4
CoreChargingHigh
LimitSwitches
Theselimitswitchesmonitorbrickcorechargingandwill
interruptpowertotheheatingelementsifthenormal
operatingtemperatureisexceeded.Eachswitchcontrols
two heating elements.
Inthelimitbarpanel
ontherightsideofthe
brickstoragecavity
Thislimitswitchmonitorsthetemperatureintheheat
exchangerofthefurnace.Ifthenormaloperatingtempera
tureisexceeded,thisswitchwillinterruptpowertothecore
blower.
Heat Exchanger High
LimitSwitch
Inthebaseofthe
furnaceinsidethe
electricalpanel
Thislimitswitchmonitorsthedischargeairtemperatureand
interruptspowertothecoreblowerifthistemperature
exceeds160
o
F(nominal).
CoreBlower High
LimitSwitch
Inthesupplyair
plenumassemblyon
theblower
Thislimitswitchmonitorsthedischargeairtemperatureand
interruptspowertothesupplyairblowerifthistemperature
exceeds180
o
F(nominal).
SupplyAirBlower
LimitSwitch
Inthesupplyair
plenumassemblyon
theblower
2
Thefilterinthefurnaceshouldbereplacedonaregularbasis.Generalcleaningofthefurnace’scabinetshouldbe
conductedattheuser’sdiscretion.Noadditionalroutinemaintenanceisrequired.
Maintenance and Cleaning
1

Furnace Control Panel 5
Furnaceoperationisautomatic;however,theusercanmanuallyoperateitbychangingsettingsonitscontrolpanel.
(SeeFigure1forreferencetolocationofthecontrolpanelandcircuitbreakersonthefurnace.)
FIGURE 1
POWER ON Light
Thisgreenindicatorlightilluminateswheneverthefurnaceisenergized.
OFFPEAK Light
Thisredindicatorlightilluminatesduringoffpeaktimeswhicharethetimeswhenthefurnaceisallowedtocharge.
(Elementscanbe"ON"tostoreheatinthebrickcore.)
HEAT CALL Light
Thisyellowindicatorlightilluminateswheneverthefurnaceisreceivingasignalfromthewallthermostattodeliver
heat.
ETSCHARGING Light
Thisredindicatorlightilluminateswhenevertheheatingelementsinthefurnaceare"ON".(Furnaceisstoringheatin
itsbrickcore.)
OUTDOOR TEMP SENSOR Lights
Theseredindicatorlightsilluminatetodesignatethebrickcorechargelevelthefurnaceistargetingwheneverthe
elementsareallowedtobe"ON".(RefertoTable1,BrickCoreChargingSchedule,inthismanualformoreinforma
tiononcharginglevelsinrelationtooutdoortemperatureandthefurnacecontrolpanelsettings.)
LEVEL1 = Illuminateswhenthefurnaceistargetingaheatstoragesettingofapproximately1/3corecharge
(500
o
F,nominal)orgreater.
LEVEL2 = Illuminateswhenthefurnaceistargetingaheatstoragesettingofapproximately2/3corecharge
(900
o
F,nominal)orgreater.
LEVEL3 = Illuminateswhenthefurnaceistargetingitsmaximumheatstoragesetting(1350
o
F,nominal).
All outdoor temperature sensor lights will be illuminated when the furnace is targeting
its maximum heat storage setting.
FURNACECONTROL
TEMPSENSOR
OUTDOOR
OVERRIDE
START
SUMMER
WINTER
CANCEL
HIGH
LOW
LEVEL3
LEVE L2
AUTO
PANEL
ETSCHARGING
HEATCALL
OFFPEAK
POWERON
LEVEL 1
CIRCUITBREAKERSCIRCUITBREAKER
BLOWERS/FURNACECONTROLS CORECHARGING(ELEMENT)
SUPPLYAIRBLOWER
PLENUMASSEMBLY
WITHHEATEXCHANGER
FURNACEBASE
NOTE

6 Furnace Control Panel (cont'd)
SUMMER/WINTER Toggle Switch
Thistoggleswitchwillvarycorecharginginthefurnace.Itallowsforareducedheatingcapacityduringthesummer
monthsiftheuserpreferstoleavethefurnace"ON"foremergencyheatpurposesduringthistime.(RefertoTable1,
BrickCoreChargingSchedule,inthismanualformoreinformationoncharginglevelsinrelationtothepositionofthis
switchandoutdoortemperature.)
AUTO/HIGH/LOW Toggle Switch
Thistoggleswitchcanbeusedtooverridetheautomaticoutdoortemperaturesensingsystem.
AUTO= Normaloperatingposition.Thebrickcorechargeleveliscontrolledautomaticallybytheoutdoor
temperature sensor.
HIGH = Thefurnacewilltargetalevel3(maximum)corechargeduringanoffpeaktimeregardlessofthe
outdoortemperatureinformationitisreceiving.
LOW = Thefurnacetargetsaminimumofalevel1(1/3)corechargeduringanoffpeaktimeunlessthe
outdoortemperaturesensorissignalingforahigherchargelevel.
OVERRIDE Light (Power Company Permitting)
Thisredlightilluminateswheneverapeakcontroloverrideisinitiatedandremainsilluminatedforthedurationofthe
overrideperiod.ThefunctionoftheoverrideindicatorlightworksinconjunctionwithSTARTandCANCELtoggle
switches.
START and CANCEL Toggle Switches (Override Feature, Power Company Permitting)
Thefurnacehasabuiltinpeakoverridefeature.Thisfeatureallowstheheatingelementsinthefurnacetocome"ON"
duringapeakcontroltimeprovidedthepowercompanypermitstheuseofthisoption.Sincenotallpowercompanies
permituseoftheoverrideoption,allfurnacesareshippedwiththisfeaturedisabled.Ifthefeatureisenabledinthe
furnace,thesetoggleswitchesinitiateandcanceltheoverrideofapeakcontroltime.
START = Initiatesanoverrideofapeakcontroltimeallowingtheheatingelementstocome"ON".The
furnacetargetsalevel1(1/3)corechargeduringanoverridecycle.Ifinitiatingthepeak
controloverridefeature,theoverridewillonlylastforthedurationofthepeakcontrolperiodat
whichtimeitresetsitselfautomaticallyunlesstheusermanuallycancelsitpriortothen.(The
overridelightwillillumniateiftheSTARTswitchistoggled.)
CANCEL = Allowsformanualcancellationofapeakoverrideanytimeduringanoverridecycle.An
overridecyclewillautomaticallycancelitselfatthestartofthenextoffpeakperiod.
The peak override option may not be available in your area.  Please consult your power
company if you are unsure of whether this option is available to you.  If so and you desire
to enable the feature, contact your power company for instructions.
NOTE

FURNACE START-UP
Onstartupofthefurnace,youmayexperiencesomeodorsrelatingtofirsttimeoperationoftheheatingcompo
nents.Theremayalsobeanodorassociatedwithdustaccumulationinthesystemifthefurnaceisshutdownfor
anextendedperiodoftime.Uponrestart,allowingthefurnacetochargetoitsmaximumbrickcorechargelevel
willhelpexpeltheseodorsinatimelymanner.
Duringoperation,itisnormalforthefurnace,likeanyheatingsystem,toproduceexpansionnoises.Thesenoises
aretheresultoftheinternalcomponentsreactingtothetemperaturechangestheyareexposedto.
ROOM TEMPERATURE CONTROL
Roomtemperatureisadjustedatthewallthermostat.Withaheatcalltothethermostat,thecoreblowerinthe
furnaceisenergizedtocirculatehotbrickcoreairthroughthefurnace’sheatexchanger.Thecoreblower
automaticallyadjustsits'speed(loworhigh)inrelationtothebrickcoretemperature.Thebloweroperatesinlow
speedwithahotbrickcoreandinhighspeedwithlowerbrickcoretemperatures.
Afterthebrickcoreairwarmstheheatexchanger,thesupplyairblowerisenergized.Thesupplyairblower
circulatestheroomairthroughtheheatexchangertowarmit;and,then,deliversitbackintothelivingspace
throughtheductsystem.
Thedelaybetweenthecorebloweroperatingandthesupplyairblowerbeingenergizedensuresonlywarm,
comfortable,evenheatisbeingdeliveredintothelivingarea.Intermittentsupplyairbloweroperationmayoccur
withlowerbrickcoretemperaturesinanefforttomaintainaconstanttemperatureandevendistributionofheat
intothelivingarea.
Somethermostatsincorporatearoomtemperaturesetbackfeaturewhichallowsforroomtemperatureto
automaticallybesetbackaspecificnumberofdegreesatspecifiedtimes.Ifusingathermostatwiththisfeature
inaprogramwherethepowercompanyhas8ormoreconsecutivehoursofcontrol,itisimportanttobringthe
roomtemperaturebacktothedesiredoccupiedtemperatureaminimumofthree(3)hoursbeforetheoffpeak
(charge)periodends.Thiswillensureoptimumheatstorageformaintainingthedesiredroomtemperature
throughouttheonpeak(control)period.
BRICK TEMPERATURE CONTROL (CORE CHARGING)
Theamountofheatstoredinthebrickcoreofthefurnaceisregulatedautomaticallyinrelationtooutdoortem
peratureandtoitscontrolpanelsettings.Theoutdoortemperaturesensorthatshipswiththefurnaceasstandard
equipmentMUSTbemountedoutside.Itprovidestemperatureinformationtothefurnaceforproperbrickcore
charging.
Instandardconfigurationfromthefactory,theoutdoorsensorsignalsthefurnacetomaintainalevel1(1/3)brick
corechargeata55
o
Foutsidetemperature,alevel2(2/3)corechargeat35
o
F,andalevel3(maximum)core
chargeat15
o
F.Attemperaturesabove55
o
F,thefurnacewillnotmaintainacorecharge;however,ifthereisa
heatcallfromthethermostatduringoffpeaktimes,1/3oftheelementswillbeenergizedtoprovideheatforthe
durationoftheheatcall.(RefertoTable1,BrickCoreChargingSchedule,formoreinformationoncharging
levelsinrelationtooutdoortemperatureandthefurnacecontrolpanelsettings.)
If outdoor temperature charging set points other than the standard configuration are pre
ferred, the sensor must be specially ordered from the factory.
Operating the Furnace 7
2
3
1
NOTE

SUMMER/WINTER OUTDOORAIR CHARGE kWINPUT(MAX) CORETEMP.
SWITCHPOSITION TEMP.(ºF) LEVEL DLF30B DLF40B ºF(Nominal)
Winter 55* 1 9.6 12.8 500
Winter 35 2 19.2 25.6 900
Winter 15 3 28.8 38.4 1,350
Summer 35 1 9.6 12.8 500
Summer 15 3 28.8 38.4 1,350
Operating the Furnace (cont'd)
8
HOW TO TURN THE FURNACE “OFF” AND “ON”
Sinceheatcallsareunlikelyduringthesummermonths,youmaywishtoturnthefurnace"OFF".Todoso,
switchall60ampcorechargingbreakerslocatedonthefrontofthefurnace’selectricalpaneltothe"OFF"
(down)position.(SeeFigure1forreferencetothelocationofthebreakersonthefurnace.)The15amp
breakershouldremain"ON"atalltimesasthisbreakeroperatestheblowersandallothercontrolsinthefurnace.
ItMUSTremain"ON"ifusingthefurnaceinconjunctionwithanairconditioningsystem.Toturnthefurnace
"ON",switchthebreakerstotheUPposition.
Foruserswhoprefertomaintainareducedheatingcapacityduringsummermonthsratherthanshuttingthe
systemoffcompletely,theSUMMER/WINTERtoggleswitchshouldbesettotheSUMMERposition.In
standardconfiguration,aSUMMERswitchsettingenablesautomaticbrickcorechargingbutatareducedlevel.
Theoutsidetemperaturemustdropbelow35
o
Fbeforecorechargingwilloccur.(RefertoTable2,BrickCore
ChargingSchedule,inthismanualformoreinformationoncharginglevelsinrelationtooutdoortemperatureand
thefurnacecontrolpanelsettings.)
* Ifduringoffpeakhoursthewallthermostatcallsforheatandtheoutdoortemperatureisabove55
o
F,1/3of
theelementswillbeenergizedforthedurationoftheheatcall.
BRICK CORE CHARGING SCHEDULE
Table 1
Duringbrickcorecharging,theheatingelementsarestaged"ON"and"OFF"in6.4kWincrements(maximum).
4
TheAUTO/HIGH/LOWtoggleswitchonthefurnacecontrolpanelwillallowtheusertooverridetheautomatic
chargecontrolsystemofthefurnace.Innormaloperation,thisswitchissettotheAUTOpostion.Regardlessof
thepositionofthisswitch,thebrickcorechargingsysteminthefurnaceisdesignedtorespondtothecoldest
temperaturesignalitisreceiving.Asaresult,ifthetoggleswitchissettoLOWandtheoutdoorsensoriscalling
forahigherbrickcoretemperaturesetting,thefurnacewillrespondtothesensorsignal.Or,shouldthecharge
level1sensorfailtorespondtooutdoortemperature,thechargelevel2or3sensorswillinitiatecorecharging.
Thisfeatureprovidescontrolredundancywhichreducesthechanceofhavinganunchargedorundercharged
brickcoreduringcoldweather.

18"
491/2"
30"
551/2"
693/4"
DLF40B 21"
511/2"
TOPVIEW
241/2"
33/4"
SLOTFOR
16"X25"FILTER
RETURNAIRDUCTIS241/2"X15"
60"
Installing The Furnace 9
1 SHIPPING
Thefurnaceisshippeddisassembledforeaseinhandlingandmovingintolocationwhereitistobeinstalled.
(RefertoTable2forinformationontheitemsshippedwitheachfurnace.)
Table 2
MODEL BRICK ELEMENTS DUCTING
(See Note 1) (See Note 2) (See Note 3)
DLF30B 28boxesWholeBrick(3/Box) 9 1BoxReturnAirFilterRack
2boxesHalfBrick(6/Box) 1BoxSupplyAirBlowerPlenumAssembly
1 Hardware Package (See Note 4)
DLF40B 37boxesWholeBrick(3/Box) 12 1OutdoorTemperatureSensor(SeeNote5)
2boxesHalfBrick(6/Box)
NOTES: 1. The furnace ships in two sections (brick storage cavity and base assembly) banded
to one pallet.
2. Each brick box weighs approximately 72 lbs each.
3. The elements are shipped inside the brick storage cabinet of the furnace.
4. The hardware package is shipped in the base assembly portion of the furnace.
5. The outdoor temperature sensor is shipped in the supply air blower plenum assem
bly box.
PLACEMENT
Thephysicaldimensionsofthefurnacealongwiththeclearancesrequiredmustbetakenintoconsideration
whenchoosingalocationforthefurnace.Theminimumareaneededfortheinstallationofafurnaceis100
squarefeet.Thebestinstallationlocationforthefurnaceisinanareaitwillbeheating.Althoughmostofthe
heatingrequirementsofthespacewillbesatisfiedbytheheatdeliveredthroughtheductsystem,asmallamount
oftheheatingrequirementswillalsobesatisfiedthroughstaticheatdissipatingthroughthefurnace'swarm
outsidepanels.Insituationswherethefurnacewillnotbeinstalledintheareaitisintendedtoheat(i.e.garage),
itisimportanttoaccountfortheheatlostthroughitspanelsbymakingproperadjustmentsinsizingofthe
furnace.
Inadditiontothephysicalspacerequirements,theweightofthefurnacemustalsobetakenintoconsideration
whenselectingtheinstallationsurface.Alevelconcreteflooristhebestsurfaceonwhichtoplacethefurnace,
butmostwellsupportedsurfacesareacceptable.Ifindoubtaboutfloorloadcapacity,consultabuildingcon
tractororarchitect.(SeeFigure2forfurnaceandductingdimensions.)
2
FIGURE 2

0" REQUIRED
CLEARANCE
2" MIN
CLEARANCE
3" MIN CLEARANCE
36" MIN CLEARANCE
TOP VIEW
0" REQUIRED
CLEARANCE
6" MIN
CLEARANCE
Installing The Furnace (cont'd)
10
CLEARANCE REQUIREMENTS
Theminimumclearancesrequiredwheninstallingthefurnaceinto
anyareaareasfollows:
BackandSides=3inches(fromcombustiblematerial)
Top=6inches(fromcombustiblematerial)
Front=36inches(foreaseofservicing)
FurnaceRightSideandAirDuct=2inches
FurnaceLeftSideandAirDuct=zeroclearance
SidesofFurnaceDucts=zeroclearance
Theclearanceareasmustbekeptopenandfreeofdebris.Donot
placeanythingontopthefurnace.Ifthefurnaceisinstalledina
small,enclosedarea(lessthan400squarefeet),theareamustbe
wellventilated.Forventilationpurposes,aminimumofa24”X24”
openingmustbeinstalled,ifnotalreadypresent,intotheareawhere
thefurnaceislocated.Inaddition,a6”X6”nonclosingtype
registermustbecutintothereturnairductofthefurnacetominimize
heatbuildupintheroom.(SeeFigure3foradepictitionofclearance
specifications.)
3
FIGURE 3
FURNACE SET-UP
For cross reference to number coded components, see
the Exploded View Diagram and the Furnace Parts List
in this manual. Refer to Table 2 in the Shipping section
of this manual for a list of items each furnace should
contain.
Step 1 Unboxthebrickstoragecabinet
Step 2 Removepaintedfrontpanel(11)ofcabinetbyremovingthesheetmetalscrewsontheloweredge.
Rotatebottomedgeofpanelouttodetachitfromthecabinet.
Step 3 Ontherightsideofthecabinet,removethescrewsaroundthelimitbarlouvrepanel(63).(See
Figure4forreferencetothelocationofthispanelandthescrews.)
Step 4 Slidethesidesandbackpaintedouterpanels(9,71,&73)backwardsasoneassemblyandremove
fromcabinet.
Step 5 Usethehandlesonthebrickstoragecabinettomoveittoitsinstallationlocation.Setasidefornow.
Removal of the limit switches (67) on the
right side of the brick storage cabinet
may be necessary to avoid damage to
these switches during the move.
Step 6 Removethebaseassembly(50)fromitsboxandmove
ittotheinstallationlocation.Discardthewooden
packagingfromthetopofthebase.Locateandset
asidethehardwarepackageshippedontopofthebase
assembly.
Do NOT install the furnace on its
shipping pallet.
4
FIGURE 4
NOTE
NOTE
NOTE
BrickStorage
Cabinet

Installing The Heater (cont'd) 11
Step 7 Adjustthelevelinglegs(48)onthebottomofthebaseassembly(50)onceitissetinfinalposition.
The leveling legs must not be extended more than one inch. The base MUST
set securely on all four legs to prevent rocking of the furnace and/or twisting of
the heat exchanger.
Step 8 Setthebrickstoragecabinetonthebaseassembly(50)takingcarenottodamagethewiringhar
nesses(65&70).
The rope gasket around the
heat exchanger inlet
and outlet of the base
assembly must be
properly adhered and
free from damage.
Damage to any
gasketing on the
furnace will result in
improper unit opera
tion and/or furnace
damage.
Step 9 Positionwiringharnesses(65&70),
andtemperaturesensingbulband
plateassembly(77)tofacilitate
routingthroughbottomrightside
panelcutout.(SeeFigure5for
referencetowiringharnesslocations
on the furnace.)
Step 10 Installthesidesandbackpainted
outerpanels(9,71&73)onthe
brickstoragecavity.Usethescrewsfoundinthehardwarepackagetosecurethepanelstothe
cabinetbyplacingthemalongbottomedgeofthepanels.
To avoid internal wire damage, use only blunt tip screws in all areas where
screw tips could come in contact with wiring.
Step 11 Installthetemperaturesensingbulbandplateassembly(77)bytighteningthescrewsinacross
patternuntilgasketiscompressed.Donotovertighten.Makecertainthatthecapillarytubeofthe
temperaturesensingassembly(77)doesnotcomeintocontactwithanyliveelectricalterminals.
Failure to seal the sensing bulb plate will cause abnormal furnace operation and
potential component damage.
Step 12 Connectthemainandelementwiringharnesses(65&70)tothelimitswitches(67).Theswitches
aremarkedwithareddotononeside.Connecttheredwirestothereddotmarkedsideofthe
switches.Connecttheblackwirestotheunmarkedsideoftheswitches.
NOTE
NOTE
NOTE
NOTE
FIGURE 5

Installing The Heater (cont'd)
12
Step 13 Connectthebrownthermocoupleleadwire(79)inthewiringharnessestothecoretemperature
sensor(68).Theyellowwireofthethermocoupleleadattachestothescrewstudmarkedwitha
yellowdot.Theredwireattachestothescrewstudmarkedwithareddot.
The brown thermocouple lead wire must be routed in a fashion that ensures it
will be protected from physical damage and does not come into contact with any
live electrical connections in the limit bar area. Incorrect polarity on the core
temperature sensor will cause the furnace to continue to charge, even when a
high charge level has been achieved.
Step 14 Carefullyinstallthelimitbarchannelingplate(61)toprovideairsealaroundwiringharnesses
(65&70).
Step 15 Installthelimitbarlouvrepanel(63).
BRICK LOADING
Step 1 Removethesheetmetalscrewsaroundtheouteredgeofthegalvanizedfrontpanel(12)andsetthe
panelaside.
Step 2 Carefullyliftthethreeinsulationblankets(3,4,&5),oneatatime,anddrapethemoverthetopof
the furnace.
Use face mask, gloves, and long sleeved garments when handling insulation
materials in accordance with generally accepted safety practices.
Step 3 Removethealuminizedsteelpanel(10)bypullingoutatthetop.
Step 4 Removetheheatingelements(17)andthepackingmaterialfromthebrickcorecavity.Toensure
adequateroomforbrickloading,thetoporbottom1"x4"(nominal)woodencorespacercanbeused
toholdinnerbrickcavitywallsapart.
The core spacer is packaging material and can be discarded after brick loading
is complete.
Step 5 Tominimizetheamountofbrickdebrisfallingintothecoreblower,placethecardboardpackaging
materialfoundinsidethebrickcavityoverthecorebloweropening.
Step 6 Loadthebrick(15),onerowatatime,startingatthebackworkingforward.Belowisalistof
installationtipstoaidinthebrickloadingprocess:
¢Besuretoremoveloose
brickdebrisasthefurnace
isbeingloadedtoprevent
unevenstackingofthe
bricks.
¢Usethehalfbrick(boxes
marked)intheproperrows
andinthecorrectpositions.
Thehalfbricksshouldbe
loadedinrows4and8inthe
DLF30andinrows5and10fortheDLF40,withrow1beingatthebottom.(SeeFigure6for
thecorrectpositionofthehalfbricks.)
The purpose of the half brick is to make brick loading easier by evening out the
stacking.  From an operation perspective, it is not essential they be placed in the
rows recommended for each model. The rows recommended simply make for the
best fit.
5
NOTE
NOTE
NOTE
NOTE
FIGURE 6
ELEMENTTERMINATION
HALFBRICK
DLF30:LOADINROWS4AND8
DLF40:LOADINROWS5AND10

¢Thesecondtolastrow,front,
middlebrickmustbethelast
brickinstalled.Ashimmaybe
usedtoholdtheupperbrickin
place,oritismoreeasily
accomplishedbyleavingthe
middlebrickinthesecondto
lastrowpulledabout4"
forwardfromitsintended
position.Inthispositionthe
brickwillactasasupportforthetopmiddlebrick.Pushthefront,middlebrickinthesecondto
lastrowintoplacewhichwillatthesametimepushthemiddlebrickthatwasleftforwardinto
place.(SeeFigure7forapicturedepictionofthisprocedure.)
INSTALLING THE HEATING ELEMENTS
Step 1 Afterallbricksareloaded,inserttheheatingelements(17)betweenthebricklayerswiththecold
pinsfacingup.(SeepicturedepictitionofelementterminationinFigure6forreferencetocoldpin
direction.)
Step 2 Maketheheatingelements(17)towiringharness(19&65)connections.(SeeFigure6forapicture
depictitionofelementtermination.)
Use two 3/8" wrenches to ensure tight connections and to avoid twisting the
threaded element cold pins off.
Step 3 Replacethefrontaluminizedsteelpanel(10).
This panel MUST be installed with its air deflectors (arrow shaped pieces) facing
inward and with the narrow ends of the deflectors pointing up.
Step 4 Lowertheinsulationblankets(3,4,&5)backintoposition,oneatatime.Carefullytuckthesidesof
thisinsulationintotheedges,corners,andaroundtheexposedportionsofheatingelements(17).
Step 5 Replacethegalvanizedfrontpanelutilizingtheoriginal#8x1"sheetmetalscrewsthatwerere
moved.
Step 6 Replacethepaintedfrontpanel(11)usingblunttipscrewsonly.
DUCTING
AirFlow
TheSteffesfurnacehasbeenspeciallydesignedforversatilityandmaybeinstalledtomeetrighttoleftorleft
torightairflowrequirements.Thefurnaceisfactoryconfiguredforalefttorightairflow.Ifitisdesiredto
reversetheairflow,dothefollowing:
Step 1 Reroutethesupplyairblowerwiringharness(55)totheoppositesideoffurnacebasebyfishingthe
harnessbetweenbottomradiantheatshield(51)andbottompanel(47).Besuretoroutethewiring
harnessawayfromthe heatexchangerandplaceanyexcesswiringbetweentheradiantheatshield
(51)andbottompanel(47).
7
Installing The Furnace (cont'd) 13
6
NOTE
NOTE
FIGURE 7
LAST(TOP)ROW
SECONDTOLASTROW
MIDDLEBRICK

Forairdelivery,thefurnaceisequippedwitha4speedsupplyairblowerwhichisfactorywiredtooperatein
mediumlowspeedforheatingandinmediumhighspeedforcoolingandafanonlythermostatsetting.The
blowerspeedmaybeadjustedforlowerorhigheroutputrequirements.Todoso,changethewiringonthe
blowerspeedselectionterminalslocatedonthesupplyairblower.(SeetheLineVoltageWiringDiagramsinthis
manualformoreinformationonthewiringandTable3forinformationonductpressurewithregardtoblower
speed.)
TABLE 3
Attaching the Ducting
Step 1 Removethesupplyairblowerplenumassembly(60)andfilterrack(18)fromtheirboxes.
Step 2 Toaccesstheblower(56),removethescrewsfromthesupplyairblowerplenumfrontaccesscover
(60)anddetachitfromtheplenum.
Step 3 Thesupplyairblower(56)isshippedbandedtotheplenumassembly(60).Cutthebandtoremove
theblowerfromtheplenumandslideitintotheplenumtrackthroughthefrontaccess.
Step 4 Attachthefrontaccesscovertotheplenum.
Step 5 Attachthesupplyairblowerplenumassembly(60)tothefurnacebydrillingtwo1/8”holesperedge.
Attachtothefurnacesupplyairsideusingtheblunttipscrewssuppliedinthehardwarepackage.
Step 6 Securethefilterrackassembly(18)onthereturnairside,againbydrilling1/8”holesperedgeand
usingtheblunttipscrewssuppliedinthehardwarepackage.Afiltershouldalreadybeincludedand
installedintheductslotofthefilterrackassembly.
Step 7 Connectboththereturnairandsupplyairhouseductstothefurnace.
If thefurnace is installed in a smallenclosed area, aminimum ofa 24" x 24" opening into
the area where the furnace is located must be installed if not already present.  In addition, a
6" x 6" nonclosing type register must be cut into the return air duct. (Refer to the Clear
ance Requirements section of this manual for more information.)
STATIC PRESSURE (INCHES WATER)
SUPPLY AIR
BLOWER SPEED 0. 10 0. 25 0. 50
HIGH Not Recommended 1850CFM 1560CFM
MEDIUM HIGH 1800CFM 1780CFM 1470CFM
MEDIUM LOW 1610CFM 1580CFM 1420CFM
LOW 1230CFM 1205CFM Not recommended
Installing The Furnace (cont'd)
14
(.20StaticMaximum)
NOTE

Furnace
CircuitBreakers
LINE2 LINE1 LINE2 LINE1
CHARGECIRCUIT#3
CHARGECIRCUIT#2
CHARGECIRCUIT#1
BLOWERS/CONTROLSCIRCUIT
CHARGECIRCUIT#4
(MODELDLF40ONLY)
LINE2 LINE1 LINE1 LINE2 LINE1 LINE2
ToServicePanel
FIGURE 8
Installing The Furnace (cont'd) 15
LINE VOLTAGE ELECTRICAL CONNECTIONS
Instandardconfiguration,thefurnaceiswiredforconnectionto240Vbutareavailablewith208Vor277V
heatingelementsasspecialfactoryorders.However,theblowersandfurnacecontrolscircuitmustalwaysbe
connectedto240Vor208V.
Thefurnaceissetupformultiplefeedcircuits.The60ampbreakerslocatedintheelectricalcompartmentat
thebaseofthe furnacefeedthecorecharging(element)circuits.The15ampbreaker feedsthefurnace
controlsandblowerscircuit.Thefurnace'selementsandblowers/controlscircuitcanbefedwithseparate
circuitsortheblowers/controlscanbefedfromoneoftheelementcircuits.Ifsinglefeedofthecharging
(element)circuitsisdesired,anoptionalsinglefeedkitisavailablefromthefactory.(Orderitem#1309000.)
Thesinglefeedkitenablesthefurnacetobefedwithasinglecircuitwhichthensplitsthiscircuitinternallyto
each breaker.
All line voltage circuits must be segregated from low voltage wiring in the furnace.
Todeterminethecorrectwiresizerequiredforeachcircuitfeedingthefurnace,refertotheUnitSpecifications
sectioninthismanual.Itistheresponsiblityoftheinstallertofollowallapplicableelectricalcodesandregula
tionsfortheinstallation.
Step 1 Removetheelectricalpanelcover(46).
Step 2 Routelinevoltagewiringthroughaknockoutandintotheelectricalpanelofthefurnace.
Step 3 Maketheproperfieldwiringconnectionstothefurnacebreakers.(SeetheLineVoltageWiring
Diagramsinthismanualformoreinformationontheseconnections.)
To reduce magnetic fields that can be produced by electrical circuits, it is rec
ommended to alternate the circuit phases in the furnace.  (See Figure 8 for more
information on how to phase connect the circuits.)
8
NOTE
NOTE

Installing The Furnace (cont'd)
16
Line Voltage Wiring Diagrams
DLF30B  240V OR 208V UNITS ONLY
FIGURE 9
Usecopperoraluminumconductorsratedfor75Corhigherforfieldconnectionofthisdevice.
NOTE
NOTES: 1.  Supply air blower speed selection terminals wiring.
2.  Line voltage field wiring connections, (see Figure 8).
350
350
350
350
350
WHITE/BLACK
BLUE/WHITE
RED
YELLOW
BLACK
WHITE
STAGING
3
1
2
3
1
2
3
1
2
N.O.
N.O.
N.O.
N.O.
N.O.
N.O.
N.O.
N.O.
STAGE1
CHARGINGSEQUENCOR
STAGE2
CHARGINGSEQUENCOR
STAGE3
CHARGINGSEQUENCOR
N.C. HEATEXCHANGERLIMIT
180°LIMIT
190° LIMIT
135°FAN
CONTROL
N.C.
N.C.
N.O.
CORE
BLOWER
N.O.
COM.
HOUSE
BLOWER N.C.
N.O.
COM.
240v24v
75VA
TRANSFORMER
10uf
Cap.
SUPPLYAIRBLOWER
HIGH
MED.HIGH
MED.LOW
LOW
COM.
COREBLOWER
HIGH
LOW
COM.
5uf
Cap.
HEATINGELEMENTS
HEATINGSPEED
BLUE/RED
COOLINGSPEED
BLUE/BLACK
SEE
NOTE#1
N.C. N.O.
COM.
170°DISK
Switchestolow
ontemp.rise
R1
125
BLACK
RED
BLUE GROUNDLUGS
BLACK
BLUE
YELLOW
RED
CONTROLS
CIRCUIT
CHARGE
CIRCUIT#1
CHARGE
CIRCUIT#2
CHARGE
CIRCUIT#3
CIRCUIT
BREAKERS
N.O.
CONTROL
135°FAN
WHITE\BLACK
BLUE
BLUE/RED
BLUE/BLACK
1
2
3
4
5
6
7
8
TOP
ROW#
BLOWERS/
SEENOTE2

Installing The Furnace (cont'd) 17
DLF40B  240V OR 208V UNITS ONLY
FIGURE 10
Usecopperoraluminumconductorsratedfor75Corhigherforfieldconnectionofthisdevice.
NOTE
NOTES: 1.  Supply air blower speed selection terminals wiring.
2.  Line voltage field wiring connections, (see Figure 8).
1
2
3
4
5
6
7
8
9
10
11
TOP
ROW#
N.O.
BLUE
BLUE/RED
COM.
COM.
N.C.
N.O.
WHITE/BLACK
CORE
HOUSE
BLOWER
BLUE/BLACK
BLOWER
WHITE\BLACK
YELLOW
BLACK
BLUE/WHITE
N.C. HEATEXCHANGERLIMIT
180°LIMIT
190° LIMIT
135°FAN
CONTROL
N.C.
N.C.
N.O.
N.O.CONTROL
135°FAN
CIRCUIT#4
CHARGE
BLOWERS/
CIRCUIT
CHARGE
CIRCUIT#1
CHARGE
CIRCUIT#2
CHARGE
CIRCUIT#3
350
350
350
350
350
350
RED
WHITE
STAGING
3
1
2
3
1
2
3
1
2
3
1
2
N.O.
N.O.
N.O.
N.O.
N.O.
N.O.
N.O.
N.O.
15A 60A 60A 60A 60A
STAGE1
CHARGINGSEQUENCER
STAGE2
CHARGINGSEQUENCER
STAGE3
CHARGINGSEQUENCER
240v24v
75VA
TRANSFORMER
10uf
Cap.
SUPPLYAIRBLOWER
HIGH
MED.HIGH
MED.LOW
LOW
COM.
COREBLOWER
HIGH
LOW
COM.
5uf
Cap.
HEATINGELEMENTS
HEATINGSPEED
BLUE/RED
COOLINGSPEED
BLUE/BLACK
SEE
NOTE1
N.C. N.O.
COM.
170°DISK
Switchestolow
ontemp.rise
R1
125
BLACK
RED
BLUE
BROWN GROUNDLUGS
BLACK
BLUE
YELLOW
RED
CONTROLS
SEENOTE2

Installing The Furnace (cont'd)
18
DLF30B AND DLF40B  277V UNITS ONLY
FIGURE 11
Usecopperoraluminumconductorsratedfor75Corhigherforfieldconnectionofthisdevice.The
blowersandthecontrolscircuitMUSTbepoweredwith240Vor208V.
NOTE
NOTES: 1.  Supply air blower speed selection terminals wiring.
2.  Line voltage field wiring connections, (see Figure 8).
HEATINGELEMENTS
N.C.
240°HEATEXCHANGERLIMIT
CHARGINGSEQUENCER
STAGE3
N.O.
N.O.
CHARGINGSEQUENCER
CHARGINGSEQUENCER
STAGE2
N.O.
N.O.
STAGE1
N.O.
N.O.
N.O.
N.O.
N.C.
LIMIT
160°
3
1
3
2
2
1
1
3
STAGING
2
BLACK
BLUE
RED
240v24v
GROUNDLUGS
(YELLOW)
277VAC
YELLOW
CORE
TRANSFORMER
BLOWER
N.O.
75VA
HOUSE
BLOWER
N.O.
N.C.
COM
135°FAN
CONTROL
CONTROL
135°FAN
N.C.
LIMIT
180°
N.O.
N.O.
COM
CIRCUIT#1
COMMON
277VOLT
60 60
CIRCUIT#1
240VAC
CIRCUIT#2 277VAC
BLACK
ontemp.rise
170°DISK
Switchestolow
N.C.
R1
RED
125
COM.
N.O.
(BROWN)
(BLACK)
LOW
COM.
HIGH
N.C.
E1
E2
E4
E3
E6
E5
E8
E7
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
N.C.
NUMBER
ELEMENT
E9 N.C.
10uf
Cap.
BLUE/RED
HEATINGSPEED
COREBLOWER
SEE
NOTE1
SUPPLYAIRBLOWER
MED.LOW
MED.HIGH BLUE
BLACK
YELLOW
RED
LOW
COM.
HIGH
60
277VAC CIRCUIT#3
Cap.
5uf
BLUE/BLACK
COOLINGSPEED
CONTROLS BLOWERS/
CHARGE CHARGE CHARGE
SEENOTE2

N.O.
N.O.
N.O.
N.O.
N.O.
N.O.
N.O.
N.O.
BACKVIEW
OFSFIII
UTILITYCONTROL
REVERSINGSWITCH
J31
J21
J41
N/A
OVERRIDE
WINTER
SUMMER
Auto
Lo
Hi
R WG C Y
AUX
Y2Y3
W G B R
TOOUTDOOR
SENSOR
N.O. N.C.
STARTCANCEL
LowVoltageField WiringConnections
Installing The Furnace (cont'd) 19
LOW VOLTAGE ELECTRICAL CONNECTIONS
Theoutdoortemperaturesensor,roomthermostat,andpeakcontrolsignalarelowvoltagewireconnectionsto
thefurnace.Alllowvoltagewiringmustbesegregatedfromlinevoltagecircuitsinthefurnace.
Low Voltage Wiring Diagram
9
NOTES: 1. Low voltage auxiliary control contacts.
a. Y to Y2 contacts open when load control device closes.
b. Y to Y3 contacts close when load control device closes.
2. Auxiliary contacts close during offpeak heat calls.
3. N.O. used for open onpeak load control device (switch closes to charge).
N.C. used for closed onpeak load control device (switch opens to charge).
FIGURE 12