Miller M7RL Series Installation guide

M7RL Series Downﬂow Condensing Gas Furnace

Direct Vent (Sealed Combustion) Forced Air

95.1% AFUE

INSTALLATION INSTRUCTIONS

HUD Manufactured Home Construction and

Safety Standards (3280.714) prohibit the use

of noncertiﬁed air conditioning or heat pump

equipment with this furnace. It is strongly

recommended that NORDYNE manufactured

housing air conditioning components

(Intertherm or Miller brands) be selected

to provide a matched system speciﬁcally

designed to meet these requirements.

The cutting, splicing or modifying of any

internal electrical wiring may void product

warranties and create a hazardous condition.

Failure to comply with these standards could

also provide inadequate heating or cooling

performance and cause structural damage

to a manufactured home.

Please contact your local Intertherm or Miller

distributor for help. A directory of NORDYNE

factory authorized service is located in the

furnace homeowner packet.

Reference: HUD Manufactured Home

Construction and Safety Standards 3280.714.

CAUTION:

DO NOT DESTROY THIS MANUAL. KEEP IN A SAFE PLACE FOR FUTURE REFERENCE.

FIRE OR EXPLOSION HAZARD

•Failure to follow safety warnings exactly

could result in serious injury or property

damage.

•Installationandservicemustbeperformed

by a qualiﬁed installer, service agency or the

gas supplier.

•Do not store or use gasoline or other

ﬂammable vapors and liquids in the vicinity

of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS

•Donottrytolightanyappliance.

•Donottouchanyelectricalswitch;donot

use any phone in your building.

•Leavethebuildingimmediately.

•Immediatelycallyourgassupplier froma

neighbor’s phone. Follow the gas supplier’s

instructions.

•Ifyoucannotreachyourgassupplier,call

the ﬁre department.

RISQUE D’INCENDIE OU D’ EXPLOSION

•Le non-respect des avertissements de

sécurité pourrait entraîner des blessures

graves, la mort ou des dommages matériels.

•L’installation et l’entretien doivent être

effectués par un installateur qualiﬁé, un

organisme de service ou le fournisseur de

gazstaller, service agency or the gas supplier.

•Nepasentreposerniutiliserdel’essenceni

d’autres vapeurs ou liquides inﬂammables

dans le voisinage de cet appareil, ni de tout

autre appareil.

QUE FAIRE S’IL Y A UNE ODEUR DE GAZ

•Nepastenterd’allumeraucunappareil.

•Netoucheràaucuninterrupteurélectrique;

n’utiliser aucun téléphone dans le bâtiment.

•Évacuerl’immeubleimmédiatement.

•Appeler immédiatement le fournisseur de

gaz en employant le téléphone d’un voisin.

Respecter à la lettre les instructions du

fournisseur de gaz.

•Sipersonnenerépond,appelerleservice

des incendies.

WARNING:

AVERTISSEMENT:

For Installation in:

• ManufacturedHomes

• ParkModels,&Manufactured

Buildings

• ModularHomes/Buildings

IMPORTANT SAFETY INFORMATION .......................3

GENERAL INFORMATION .......................................... 4

Requirements&Codes............................................4

ClearancestoCombustibleMaterials.......................5

CombustionAirQuality.............................................5

HeatingLoad............................................................5

CondensateDisposal...............................................5

COMBUSTION AIR & VENTING REQUIREMENTS ....6

ImportantInformation...............................................7

CategoryIVAppliances............................................7

DirectVentInstallation..............................................7

VentPipeLength&Diameter................................. 7

VentPipeMaterial.................................................. 8

VentPipeInstallation.............................................. 8

OutdoorTerminations-HorizontalVenting............. 8

OutdoorTerminations-VerticalVenting................. 9

VentFreezingProtection...................................... 10

ExistingInstallations............................................. 10

VentilaireIIIorIVAirQualityPackage................... 10

CIRCULATING AIR REQUIREMENTS ...................... 11

Plenums&AirDucts.............................................. 11

SupplyAirConnections.......................................... 11

ReturnAirConnections.......................................... 11

Closet&AlcoveInstallations.................................. 12

FurnaceFilter......................................................... 12

Dampers................................................................. 12

AcousticalTreatments............................................ 12

FURNACE INSTALLATION ....................................... 13

AbouttheFurnace.................................................. 13

BeforeYouInstallthisFurnace............................... 13

LocatingtheUnit.................................................... 13

Locating&CuttingFloorOpenings...................... 14

Locating&CuttingCeilingOpenings.................... 14

InstallingFingerTabbedDuctConnectors............. 14

NarrowDuctAttachment-Option1...................... 15

NarrowDuctAttachment-Option2...................... 15

InstallingScrew-DownDuctConnectors................ 16

InstallingRoundDuctConnectors.......................... 16

InstallingtheFurnace............................................. 16

CondensateDrainage............................................ 16

GAS SUPPLY & PIPING ............................................ 17

LeakCheck........................................................... 18

High-AltitudeApplication........................................ 19

ConvertingtoLP/PropaneGas............................ 19

RemovingtheBurnerOrices.............................. 20

GasPressureAdjustment...................................... 20

MeasuringtheSupplyGasPressure.................... 20

Lighting&AdjustmentoftheAppliance................ 21

MeasuringtheManifoldPressure......................... 21

AdjustingtheManifoldPressure........................... 21

RemovingtheManometer/PressureGauge...... 21

CompletingtheConversion.................................... 21

ELECTRICAL WIRING ............................................... 22

LineVoltageWiring................................................ 22

Thermostat/LowVoltageConnections................. 22

HeatAnticipator.................................................... 23

Grounding............................................................... 23

START-UP&ADJUSTMENTS ................................... 24

Pre-StartChecklist................................................. 24

Start-UpProcedures.............................................. 24

Verifying&AdjustingInputRate............................. 24

Verifying&AdjustingTemperatureRise................. 24

VerifyingBurnerOperation..................................... 25

VerifyingOperationoftheSupplyAir

LimitSwitch............................................................ 25

OPERATING SEQUENCE ......................................... 26

HeatingCycle......................................................... 26

CoolingCycle......................................................... 26

FanMode............................................................... 26

MAINTENANCE ......................................................... 26

AirFilters................................................................ 27

BlowerCompartment.............................................. 27

CleaningofBurners................................................ 27

VentSystem........................................................... 27

HeatExchanger&BurnerMaintenance................. 27

Lubrication.............................................................. 27

TROUBLESHOOTING ............................................... 28

DESCRIPTION OF COMPONENTS .......................... 28

FIGURES & TABLES ................................................. 29

FurnaceDimensions............................................... 29

Figure23-ACabinetModels(Short)................... 29

Figure24-BCabinetModels(Tall)...................... 30

Figure25-BCabinetModels(TopReturnAir).... 31

WiringDiagram....................................................... 32

Figure26-M7RLWiringDiagram........................ 32

GasInformation...................................................... 33

Table8-GasFlowRates..................................... 33

Table9-GasPipeCapacities.............................. 33

Table10-HighAltitudeDerationChartfor

PropaneGas....................................... 34

Table11-Natural

GasHeatingValues.................34

Table12-HighAltitudeDerationChartfor

Nat.Gas-HighHeatingValues........... 34

Table13-HighAltitudeDerationChartfor

Nat.Gas-LowHeatingValues............ 34

VentingInformation................................................ 35

Table14-VentTerminationClearances............... 35

Figure27-Horizontal&VerticalVenting.............. 36

INSTALLATION / PERFORMANCE CHECKLIST ..... 40

TABLE OF CONTENTS

IMPORTANT SAFETY INFORMATION

INSTALLER:Pleasereadallinstructionsbeforeservicing

thisequipment.Payattentiontoallsafetywarningsand

anyotherspecialnoteshighlightedinthemanual.Safety

markingsareusedfrequentlythroughoutthismanualto

designateadegreeorlevelofseriousnessandshould

notbeignored.

WARNING indicates a potentially hazardous situation

thatifnotavoided,couldresultinpersonalinjuryordeath.

CAUTIONindicatesapotentiallyhazardoussituationthat

ifnotavoided,mayresultinminorormoderateinjuryor

propertydamage.

• Tominimizeequipmentfailureorpersonalinjury,itis

essentialthatonlyqualiedindividualsinstall,service,or

maintainthisequipment.Ifyoudonotpossesmechanical

skillsortools,callyourlocaldealerforassistance.

• Follow all precautions in the literature, on tags, and

on labels provided with the equipment. Read and

thoroughlyunderstand the instructions providedwith

theequipmentpriortoperformingtheinstallationand

operationalcheckoutoftheequipment.

• Usecautionwhenhandlingthisapplianceorremoving

components.Personalinjurycanoccurfromsharpmetal

edgespresentinallsheetmetalconstructedequipment.

• Donotstoreanyofthefollowingon,orincontactwith,

the unit: Rags, brooms, vacuum cleaners, or other

cleaningtools,sprayoraerosolcans,soappowders,

bleaches, waxes, cleaning compounds, plastics or

plasticcontainers,paperbagsorotherpaperproducts,

gasoline,kerosene,cigarettelighteruid,drycleaning

uids,paintthinners,orothervolatileuids.

• Installationofequipmentmayrequirebrazingoperations.

Installer must comply with safety codes and wear

appropriate safety equipment (safety glasses, work

gloves,reextinguisher,etc.)whenperformingbrazing

operations.

• Theinstallershouldbecomefamiliarwiththeunitswiring

diagrambeforemakinganyelectricalconnectionstothe

unit.SeetheunitwiringlabelorFigure26(page32).

• Always reinstallthedoorsontheindoor blowerafter

servicingorcleaning/changingthelters.Donotoperate

theindoorblowerwithoutalldoorsandcoversinplace.

WARNING:

The safety information listed in this manual

must be followed during the installation,

service, and operation of this unit. Unqualiﬁed

individuals should not attempt to interpret these

instructions or install this equipment. Failure

to follow safety recommendations could result

in possible damage to the equipment, serious

personal injury or death.

WARNING:

ELECTRICAL SHOCK, FIRE OR EXPLOSION

HAZARD

Failuretofollowsafetywarningsexactlycould

result in serious injury or property damage.

Improper servicing could result in dangerous

operation, serious injury, death or property

damage.

• Before servicing, disconnect all electrical

power to the indoor blower.

• Whenservicingcontrols,labelallwiresprior

to disconnecting. Reconnect wires correctly.

• Verifyproperoperationafterservicing.

WARNING:

FIRE OR EXPLOSION HAZARD

•Failuretofollowsafetywarningsexactlycould

result in serious injury or property damage.

•Installationandservicemustbeperformedby

a qualiﬁed installer, service agency or the gas

supplier.

•Donotstoreorusegasolineorotherammable

vapors and liquids in the vicinity of this or any

other appliance.

WHAT TO DO IF YOU SMELL GAS

•Donottrytolightanyappliance.

•Donottouchanyelectricalswitch;donotuse

any phone in your building.

•Leavethebuildingimmediately.

•Immediately call your gas supplier from a

neighbor’s phone. Follow the gas supplier’s

instructions.

•Ifyoucannotreachyourgassupplier,callthe

ﬁre department.

WARNING:

Improper installation, service, adjustment,

or maintenance may cause explosion, re,

electrical shock or other hazardous conditions

which may result in personal injury or property

damage. Unless otherwise noted in these

instructions, only factory authorized kits or

accessories may be used with this product.

WARNING:

Unless otherwise noted in these instructions,

only factory authorized kits or accessories may

be used with or when modifying this product.

GENERAL INFORMATION

Requirements & Codes

WARNING:

This unit must be installed in accordance with

instructions outlined in this manual during

the installation, service, and operation of

this unit. Unqualiﬁed individuals should not

attempt to interpret these instructions or

install this equipment. Failure to follow safety

recommendations could result in possible

damage to the equipment, serious personal

injury or death..

• The installer must comply with all local codes and

regulationswhichgoverntheinstallationofthistype

of equipment. Local codes and regulations take

precedenceoveranyrecommendationscontainedin

theseinstructions.Consultlocalbuildingcodesandthe

NationalElectricalCode(ANSICI)forspecialinstallation

requirements.

• Allelectricalwiringmustbecompletedinaccordance

withlocal,stateandnationalcodes and regulations

andwiththeNationalElectricCode(ANSI/NFPA70)

orinCanadatheCanadianElectricCodePart1CSA

C.22.1.

• This furnace must be installed in accordance with

theseinstructions,allapplicablelocalbuildingcodes

andthecurrentrevisionoftheNationalFuelGasCode

(NFPA54/ANSIZ223.1)ortheNaturalGasandPropane

InstallationCode,CAN/CGAB149.1.

• Useonlywithtypeofgasapprovedforthisfurnace.

Refertothefurnaceratingplate.

• Installthisfurnaceonlyinalocationandpositionas

speciedonpage13.

• Provideadequatecombustionandventilationairtothe

furnacespaceasspeciedonpages6-7.

• Provideadequateclearancesaroundtheventairintake

terminalasspeciedinFigures1-4(page9).

• Combustionproducts must be dischargedoutdoors.

Connectthisfurnacetoanapprovedventsystemonly,

asspeciedonpages7-10.

• Nevertest for gasleaks withan open ame. Use a

commercially available soap solution to check all

connections.Seepages17-18.

• Thisfurnaceisdesignedtooperatewithamaximum

externalpressureriseof0.3inchesofwatercolumn.

ConsultTable6(page25)andtheratingplateforthe

propercirculatingairowandtemperaturerise.Itis

importantthattheductsystembedesignedtoprovide

thecorrectowratesandexternalpressurerise.An

improperlydesignedductsystemcanresultinnuisance

shutdowns,andcomfortornoiseissues.

• Thisfurnacemustnotbeusedfortemporaryheating

ofbuildingsorstructuresunderconstruction.

• The Commonwealth of Massachusetts requires

compliancewithregulation248CMR4.00and5.00for

installationofthrough–the–wallventedgasappliances

asfollows:

1.For direct-vent appliances, mechanical-vent heating

appliancesordomestichotwaterequipment,wherethe

bottomoftheventterminalandtheairintakeisinstalled

belowfourfeetabovegradethefollowingrequirements

mustbesatised:

a.)Acarbonmonoxide(CO)detectorandalarmshallbe

placedoneachoorlevelwheretherearebedrooms.

The detectorshall complywith NFPA 720 (2005

Edition)andbemountedinthelivingareaoutside

thebedroom(s).

b.)A(CO)detectorshallbelocatedintheroomthat

housestheapplianceorequipmentandshall:

•Bepoweredbythesameelectricalcircuitasthe

applianceorequipment.Onlyoneserviceswitch

shallpowertheapplianceandthe(CO)detector;

•Havebatteryback-uppower;

•MeetANSI/UL2034Standardsandcomplywith

NFPA720(2005Edition);andApprovedandlisted

byaNationallyRecognizedTestingLaboratoryas

recognizedunder527CMR.

c.)AProduct-approvedventterminalmustbeused,

andifapplicable,aproduct-approvedairintakemust

beused.Installationshallbeinstrictcompliance

with the manufacturer’s instructions. A copy of

the installation instructions shall remain with the

appliance or equipment at the completion of the

installation.

d.)Ametalorplasticidenticationplateshallbemounted

attheexteriorofthebuilding,4feetdirectlyabove

thelocationofventterminal.Theplateshallbeof

sufcientsize,easilyreadfromadistanceofeight

feetaway,andread“GasVentDirectlyBelow”.

2.For direct-vent appliances, mechanical vent heating

appliancesordomestichotwaterequipmentwherethe

bottomoftheventterminalandtheairintakeisinstalled

abovefourfeetabovegradethefollowingrequirements

mustbesatised:

a.)A(CO)detectorandalarmshallbeplacedoneach

oorlevelwheretherearebedrooms.Thedetector

shallcomplywithNFPA720(2005Edition)andbe

mountedinthelivingareaoutsidethebedroom(s).

b.)The(CO)detectorshall:

•Belocatedintheroomthathousestheappliance

orequipment;

•Behard-wired,batterypoweredorboth.

•ShallcomplywithNFPA720(2005Edition).

c.)A product-approved ventterminal must be used,

andifapplicable,aproduct-approvedairintakemust

beused.Installationshallbeinstrictcompliance

with the manufacturer’s instructions. A copy of

the installation instructions shall remain with the

appliance or equipment at the completion of the

installation.

Clearances to Combustible Materials

ThisfurnaceisDesignCertiedintheU.S.andCanada

by CSA International for the minimum clearances to

combustible materials. NOTE:The furnaceis listed for

installationoncombustibleornon-combustibleooring.

However,woodistheonlycombustibleooringallowed

forinstallation.Toobtainfurnacebasemodelnumberand

specicclearanceinformation,refertothefurnacerating

plate,locatedinsideofthefurnacecabinet.

Access for positioning and servicing the unit must be

considered when locating unit. The need to provide

clearance for access to panels or doors may require

clearancedistances over and abovethe requirements.

Allow 18 inches minimum clearance from the front of

the unit. However 36 inches is strongly recommended.

SeeTable1forminimumclearancerequirements.

Theductworkshouldbeappropriatelysizedtothecapacity

of the furnace to ensure its proper airow rating. For

installationsabove2,000ft.,thefurnaceshouldhavea

sealevelinputratinglargeenoughthatitwillmeetthe

heatingloadafterderationforaltitude.

Combustion Air Quality

CAUTION:

Combustion air must not be drawn from a

corrosive atmosphere.

To maximize heat exchanger life, the combustion air

mustbefreeofchemicalsthatcanformcorrosiveacidic

compoundsinthecombustiongases.Therequiredsource

ofcombustionairistouseoutdoorair.

Exposuretothefollowingsubstancesinthecombustion

airsupplywillresultinsafetyandperformancerelated

problems.Thelistbelowcontainsexamplesofchemical

containments found in a wide variety of common

commercialhouseholdproducts:

•Permanentwavesolutions

•Chlorinatedwaxesandcleaners

•Chlorinebasedswimmingpoolchemicals

•Watersofteningchemicals

•De-icingsaltsorchemicals

•CarbonTetrachloride

•Halogentyperefrigerants

•Cleaningsolvents(perchloroethylene)

•Printinginks,paintremovers,varnishes,etc.

•HydrochloricAcid

•Cementsandglues

•Antistaticfabricsofteners

•Masonryacidwashingmaterials

Heating Load

Thisfurnaceshouldbesizedtoprovidethedesignheating

loadrequirement.Heatingloadestimatescanbemade

usingapprovedmethodsavailablefromAirConditioning

ContractorsofAmerica(ManualJ);AmericanSocietyof

Heating,Refrigerating,andAirConditioningEngineers;

or other approved engineering methods. Excessive

oversizing of the furnace could cause the furnace

and/or vent to fail prematurely.

Condensate Disposal

Themethodfordisposingofcondensatevariesaccording

tolocalcodes.Consultyourlocalcodeorauthorityhaving

jurisdiction. Neutralizer kit P/N 902377 is available for

use with thisfurnace. Please follow the instructions

provided with the kit.

Table 1. Minimum Clearance Requirements

INSTALLATION CLEARANCES

CLOSET ALCOVE

Front* 1" 1"

Rear 0" 0"

Sides 0" 0"

To p 6" 6"

Ductw/in3ftoffurnace 1/4" 1/4"

Vent 0” 0”

PlenumWithoutCoilBox 1" 1"

PlenumWithCoilBox 0” 0”

NOTES:

AlcoveInstallations-Allow18in.minimumclearance

fromfrontofunittonearestwallorpartitionforservicing.

Closetinstallations-Requireareturnairgrillinstalled

in the door or a partially louvered door across the

opening forproper air circulation. For clearances 6”

orgreater,theclosetmusthaveanopenfreeareaof

235in

minimum.Forspecialclearancesbetween1”&

6”,requirementsarealouvereddoorwithaminimum

of250in

(1613cm

)freearea.For1”clearancefrom

furnace, use afully louvereddoor with atleast 400

2

offreeairowarea.Afullylouveredclosetdooris

stronglyrecommendedforallinstallationtypes.

LEFT

SIDE

FRONT

RIGHT

SIDE

REAR

RIGHT

SIDE

SHORT A-SIZE CABINET & TALL B-SIZE CABINET TALL B-SIZE CABINET WITH TOP AIR RETURN

REAR

LEFT

SIDE

FRONT

VENT

COMBUSTION AIR & VENTING REQUIREMENTS

WARNING:

CARBON MONOXIDE POISONING HAZARD

Failure to follow the steps outlined below for

each appliance connected to the venting system

being placed into operation could result in carbon

monoxidepoisoningordeath.Thefollowingsteps

shall be followed with each individual appliance

connected to the venting system being placed in

operation, while all other appliances connected to

the venting system are not in operation:

1. Seal any unused openings in the venting

system.

2. Inspect the venting system for proper size and

horizontal pitch, as required in the National Fuel

Gas Code, ANSI Z223.1/NFPA 54 or the CSA

B149.1, Natural Gas and Propane Installation

Codes and these instructions. Determine that

there is no blockage or restriction, leakage,

corrosion and other deﬁciencies which could

cause an unsafe condition.

3. As far as practical, close all building doors and

windows and all doors between the space in

which the appliance(s) connected to the venting

system are located and other spaces of the

building.

4. Close ﬁreplace dampers.

5. Turn on clothes dryers and any appliance

not connected to the venting system. Turn on

anyexhaustfans,suchasrange hoodsand

bathroomexhausts,sotheyareoperatingat

maximum speed. Do not operate a summer

exhaustfan.

6. Follow the lighting instructions. Place the

appliance being inspected into operation.

Adjust the thermostat so appliance is operating

continuously.

7. Test for spillage from draft hood equipped

appliances at the draft hood relief opening

after 5 minutes of main burner operation. Use

the ﬂame of a match or candle.

8. If improper venting is observed during any of

the above tests, the venting system must be

corrected in accordance with the National Fuel

Gas Code, ANSI Z223.1/NFPA 54 and/or CSA

B149.1, Natural Gas and Propane Installation

Codes.

9. After it has been determined that each appliance

connected to the venting system properly vents

when tested as outlined above, return doors,

windows,exhaustfans,replacedampersand

anyothergas-redburningappliancetotheir

previous conditions of use.

AVERTISSEMENT:

RISQUE D’EMPOISONNEMENT AU

MONOXYDE DE CARBONED

Le non-respect des consignes suivantes portant

sur chacun des appareils raccordés au système

d’évacuation mis en service pourrait entraîner

l’empoisennement au monoxyde de carbone ou

la mort. Les consignes suivantes doivent être

observées pour chaque appareil raccordé au système

d’évacuation mis en service si les autres appareils

raccordés au système ne sont pas en service:

1. Sceller toute ouverture non utilisée de la systéme

d’évacuation;

2. S’assurer que la systéme d’évacuation présente

des dimensions et une pente horizontale

conformes à la norme ANSI Z223.1/NFPA

54, intitulée National Fuel Gas Code ou aux

codes d’installation CSA-B149.1, ainsi qu’aux

présentes instructions. S’assurer que la systéme

d’évacuation n’est pas bloquée, restreinte,

corrodée, qu’elle ne fuit pas et qu’elle ne présente

aucunautredéfautpotentiellementdangereux;

3. Dans la mesure du possible, fermer toutes les

portesetfenêtresdubâtiment,ettouteslesportes

entrelapièceoùsetrouvel’appareilraccordéà

la systéme d’évacuation et les autres pièces du

bâtiment.

4.Fermerlesregistresdesfoyers;

5. Mettre en service les sécheuses et tout autre

appareil qui n’est pas raccordé à la systéme

d’évacuation.Fairefonctionneràrégimemaximal

tout ventilateur d’évacuation, tel que les hottes de

cuisinière et les ventilateurs de salles de bains.

Ne pas mettre en service les ventilateurs d’été.

6. Respecter les instructions d’allumage. Mettre en

servicel’appareilàl’essai.Réglerlethermostat

demanièreàcequel’appareilfonctionnesans

interruption;

7.Vérifier s’il y a débordement à l’orifice

d’évacuation du coupe tirage des appareils dotés

d’un coupe tirage 5 minutes après l’allumage

du brûleur principal. Utiliser la ﬂamme d’une

allumette ou d’une chandelle.

8. Si l’on constate, au cours de l’un des essais

qui précèdent, que l’évacuation est déﬁciente,

corriger le système d’évacuation conformément

àla normANSIZ223.1/NFPA54,National Fuel

GasCode,et(ou)auxcodesd’installationCSA

B149.1.

9. Après avoir déterminé que tous les appareils

raccordésàlasystémed’évacuationévacuent

correctement tel que prescrit ci-dessus,

rouvrirlesportesetlesfenêtresetremettreles

ventilateurs d’évacuation, les registres de foyers

ettoutautreappareilfonctionnantaugazàleur

état de fonctionnement initial.

Direct Vent Installation

Thiscondensingfurnaceiscertiedforinstallationasa

DirectVent(2-pipe)appliance.DirectVent(2-pipe)furnaces

drawcombustionairdirectlyfromtheoutdoorsandthen

ventthecombustionproductsbackoutside,isolatingthe

entiresystemfromtheindoorspace.Itisimportanttomake

surethatthewholesystemissealedandclearancesto

combustiblesaremaintainedregardlessoftheinstallation

being in a conned or unconned space.This section

speciesinstallationrequirementsforDirectVent(2-pipe)

piping.Table2(page8)containsthelengthofventand

combustionairpipingforthistypeofinstallation.

Provisionsmustbemadeduringtheinstallationofthis

furnacethatprovideanadequatesupplyoffreshairfor

combustionandventilation.Thecombustionairfromthe

outsideneedstobeclearofchemicalsthatcancause

corrosion. The inlet pipe should not be placed near

corrosivechemicalssuchasthoselistedonpage5.

Airopeningsontopofthefurnaceandopeningsincloset

doorsorwallsmustneverberestricted.Ifthefurnaceis

operatedwithoutadequateairforcombustion,theame

roll-outswitchwillopen,turningoffthegassupplytothe

burners.NOTE:This safety device is a manually reset

switch. DO NOT install jumper wires across these

switches to defeat their function or reset a switch

without identifying and correcting the fault condition.I f 

aswitchmustbereplaced,useonlythecorrectsizedpart

speciedintheReplacementPartsListprovidedonline.

VentPipeLength&Diameter

Forproperfurnaceoperation,thecombustionairandvent

pipingmustnotbeexcessivelyrestrictive.

• Theventingsystemshouldbedesignedtohavethe

minimumnumberofelbowsorturns.

• Allhorizontalrunsmustslopeupwardsfromthefurnace

at1/4inchminimumperrunningfootofvent.

• Transitiontothenalventdiametershouldbedoneas

closetothefurnaceoutletaspractical.

• Alwaysusethesamesizeoralargerpipeforcombustion

airthatisusedfortheexhaustvent.

Table2(page8)indicatesthemaximumallowablepipe

lengthforafurnaceofknowninputrate,wheninstalled

withpipingofselecteddiameterandnumberofelbows.To

usethetable,thefurnaceinputrate,thecenterlinelength

andthenumberofelbowsoneachpipemustbeknown.

Whenestimatingthelengthofventruns,consideration

mustbemadetotheeffectofelbowsandotherttings.

Thisisconvenientlyhandledusingtheideaof“equivalent

length”.Thismeansthettingsareassignedalinearlength

thataccountsforthepressuredroptheywillcause.For

example:a3”diameter,longradiuselbowisworththe

equivalentof3.5feetoflinearrun.

Theequivalentlenghtsofteesandvariouselbowsare

listedinTable2.Measurethelinearlengthofyourventrun

andthenaddintheequivalentlengthofeachtting.The

Important Information

WARNING:

Furnace installation using methods other than

those described in the following sections must

comply with the National Fuel Gas Code (NFGC)

and all applicable local codes.

WARNING:

Upon completion of the furnace installation,

carefully inspect the entire ﬂue system both

inside and outside the furnace to assure it is

properly sealed. Leaks in the ﬂue system can

result in serious personal injury or death due

toexposureofueproducts,includingcarbon

monoxide.

WARNING:

This furnace must not be vented with other

appliances, even if that appliance is of the

condensing type. This includes water heaters

of any efﬁciency. Common venting can result

in severe corrosion of other appliances or their

venting and can allow combustion gases to

escape through such appliances or vents. Do

not vent the furnace to a ﬁreplace chimney or

building chase.

• This furnace must be vented in compliance with

the current revision of the National Fuel Gas Code

(ANSI-Z223.1/NFPA54). Instructions for determining

the adequacy of combustion air for an installation

can be found in the current revision of the NFGC

(ANSI Z223.1 / NFPA54). Consult local codes for

special requirements. These requirements are for

USinstallationsasfoundintheNFGC.

• TherequirementsinCanada(B149.1)arestructured

differently. In Canada, venting shall conform to the

requirementsofthecurrent(CAN/CGAB149.1or.2)

installationcodes.Consult local codes for special

requirements.

Category IV Appliances

Thisfurnaceisclassiedasa“CategoryIV”appliance,

whichrequiresspecialventingmaterialsandinstallation

procedures.CategoryIVappliancesoperatewithpositive

ventpressureandrequiresthoroughlysealedventsystems.

Theyalso produce liquid condensate, which isslightly

acidicandcancauseseverecorrosionofordinaryventing

materials.Furnaceoperationcanbeadverselyaffected

byrestrictiveventandcombustionairpiping.

MaximumDirectVent,DualPipeLength(FT.)

FURNACE MODELS

(BTU)

INLET / OUTLET

3” Diameter

45,000 60

60,000 60

72,000 60

†

NOTES:

1Subtract3.5ft.foreachadditional3inchlongradiuselbow,and

7ft.foreachadditional3inchshortradiuselbow.

2.Two45degreeelbowsareequivalenttoone90degreeelbow.

3.Thistableappliesforelevationsfromsealevelto2,000ft.For

higherelevations,decreasepipelengthsby8%per1,000ftof

altitude.

Table 2. Vent Pipe Lengths

cause corrosion of the furnace combustion system.

(Seepage5forasamplelistofsubstances).

• Routepipingasdirectaspossiblebetweenthefurnace

and the outdoors. Longer vent runs require larger

diameters.Ventpipingmustbeslopedupwards1/4”

perfootinthedirectionfromthefurnacetotheterminal.

Thisensuresthatanycondensateowsbacktothe

condensatedisposalsystem.

• When a Direct Vent (2-pipe) system is used, the

combustionairintakeandtheventexhaustmustbe

locatedinthesameatmosphericpressurezone.This

meansbothpipesmustexitthebuildingthroughthe

sameportionofexteriorwallorroofasshowninFigure

27,page36.

• Piping must be mechanically supported so that its

weightdoesnotbear onthefurnace.Pipesupports

mustbeinstalledaminimumofeveryvefeetalongthe

ventruntoensurenodisplacementafterinstallation.

Supportsmaybeatshorterintervalsifnecessaryto

ensurethattherearenosaggingsectionsthatcantrap

condensate. It is recommended to install couplings

alongtheventpipe,oneithersideoftheexteriorwall

(Figure27).Thesecouplingsmayberequiredbylocal

code.

• Ifbreakableconnectionsarerequiredinthecombustion

airinletpipe(ifpresent)andexhaustventpiping,then

straight neoprene couplings for 3” piping with hose

clampscanbeused.Thesecouplingscanbeordered

through your local furnace distributor. To install a

coupling:

1. Slidetherubbercouplingovertheendofthepipe

thatisattachedtothefurnaceandsecureitwith

oneofthehoseclamps.

2. Slidetheotherendoftherubbercouplingontothe

otherpipefromthevent.

3. Securethecouplingwiththesecondhoseclamp,

ensuringthattheconnectionistightandleakfree.

OutdoorTerminations-HorizontalVenting

• Ventandcombustionairintaketerminationsshallbe

installedasshowninFigures1&2(page9)andin

accordancewiththeseinstructions:

• Ventterminationclearancesmustbeconsistentwiththe

NFGC,ANSI2223.1/NFPA54and/ortheCSAB149.1,

NaturalGasandPropaneInstallationCode.Table12

(page32)liststhenecessarydistancesfromthevent

terminationtowindowsandbuildingairintakes.

• Vent and combustion air intake terminations must

be located to ensure proper furnace operation and

conformance to applicable codes. A vent terminal

mustbelocatedatleast3feetaboveanyforcedair

inletlocatedwithin10feet.Thisdoesnotapplytothe

combustionairinletofadirectvent(twopipe)appliance.

InCanada,CSAB149.1takesprecedenceoverthese

instructions.SeeTable14(page35).

• Allminimumclearances(Figure2)mustbemaintained

toprotectbuildingmaterialsfromdegradationbyue

gases.

totallength,includingtheequivalentttinglengths,must

belessthanthemaximumlengthspeciedinthetable.

Condensingfurnacecombustionproductshaveverylittle

buoyancy,soTable2istobeusedwithoutconsideration

ofanyverticalriseinthepiping.

VentPipeMaterial

Ventandcombustionairpipeandttingsmustbeoneof

thefollowingmaterialsinthelistandmustconformtothe

indicatedANSI/ASTMstandards.Cementmustconform

toASTMStandardD2564forPVCandStandardD2235

forABS.PVCprimermustmeetstandardASTMF656.

WhenjoiningPVCpipingtoABS,usePVCsolventcement.

(SeeprocedurespeciedinASTMStandardD3138).

In Canada, all plastic vent pipes and ttings including

anycement,cleaners,orprimersmustbecertiedasa

systemtoULCS636.Howeverthisrequirementdoesnot

applytopipinginternaltothefurnace.

Materials Standards

SCHEDULE40PVC............................................... D1785

PVC-DWV.............................................................. D2665

SDR-21&SDR-26................................................. D2241

ABS-DWV.............................................................. D2661

SCHEDULE40ABS.............................................. F628

FOAM/CELLULARCOREPVC........................... F891

VentPipeInstallation

CAUTION:

Combustion air must not be drawn from a

corrosive atmosphere.

Thisfurnacehasbeencertiedforinstallationwithzero

clearancebetweenventpipingandcombustiblesurfaces.

However,itisgoodpracticetoallowspaceforconvenience

ininstallationandservice.

• Thequalityofoutdoorairmustalsobeconsidered.Be

surethatthecombustionairintakeisnotlocatedneara

sourceofsolventfumesorotherchemicalswhichcan

• For optimal performance, vent the furnace through

awallthat experiencestheleastexposuretowinter

winds.

• The vent termination shall be located at least 3 ft.

horizontallyfromanyelectricmeter,gasmeter,regulator

andanyreliefequipment.ThesedistancesapplyONLY

to U.S. installations. In Canada, CSA B149.1 takes

precedenceovertheseinstructions.

• Donotinstalltheventterminal suchthatexhaustis

directed into window wells, stairwells, under decks

orintoalcovesorsimilarrecessedareas,anddonot

terminateaboveanypublicwalkways.

• Ifventinghorizontally,sidewallventkitsareavailable

accordingtothepipediametersizeoftheinstallation.

For3inchpipe,usekit#904347.Faceplatekit#902375

isalsoavailablefor3inchhorizontalventing.Please

follow the instructions provided with the kits.

• Concentricventterminationkitsareavailableforuse

withthesefurnaces.For3inchpipeusekit#904953.

Please follow the instructions provided with the kit.

• Whentheventpipemustexitanexteriorwallcloseto

thegradeorexpectedsnowlevelwhereitisnotpossible

toobtainclearancesshowninFigure1,arisermaybe

providedasshowninFigure3.Insulationisrequired

topreventfreezingofthissectionofpipe.SeeTable3

(page10)forventfreezingprotection.

OutdoorTerminations-VerticalVenting

Terminationspacingrequirementsfromtheroofandfrom

eachotherareshowninFigure4.Theroofpenetration

mustbeproperlyashedandwaterproofedwithaplumbing

roofbootorequivalentashing.Ventandcombustionair

pipingmaybeinstalledinanexistingchimneywhichis

notinuseprovidedthat:

• Boththeexhaustventandairintakerunthelengthof

thechimney.

• Thetopofthechimneyissealedandweatherproofed.

• The termination clearances shown in Figure 4 are

maintained.

• Noothergasredorfuel-burningequipmentisvented

throughthechimney.

12” min. to maximum

expected snow level

(both pipes)

90° Elbow

Exhaust vent

option B

Exhaust vent

option A

Mounting kit faceplate

secured to wall with screws

(both pipes)

Combustion

air inlet

Exhaust vent

option C

18” Min.

36” Max.

8” Min.

36” Max.

(all positions)

Figure1.Inlet&ExhaustPipeClearances

Note 2

Mechanical draft

vent terminal

Direct vent

terminal

50,000 Btuh

or less

Forced air inlet

Direct vent

terminal - more

than 50,000 Btuh

Mechanical

draft vent

terminal

Mechanical

draft vent

terminal

Less

than

10 ft.

3 ft.

NOTES:

1. All dimensions shown are

minimum requirements.

2. Exterior vent terminations must

be located at least 12” above the

maximum expected snow level.

Note 2

4 ft

12 in.

9 in.

Note 2

Figure 2. Vent Locations

Support

NOTE: Vent Configuration to Provide

12" Minimum height above Snow Level.

1/2"

Armaflex

Insulation or

Equivalent

(if required)

12" Above

Maximum

Expected

Snow Level

19" Max.

(See Note)

Outside

Wall

Figure 3. Alternate Horizontal Vent Installation

Figure 4. Vertical Vent Termination

Combustion Air

Exhaust Vent

12” Above Maximum

Expected Snow Level

(Both pipes)

Elbows on the combustion air

inlet must be positioned pointing

away from the exhaust vent.

8" Min.

36" Max.

Plumbing Vent Roof Boot

(Both Pipes)

ExistingInstallations

Whenanexistingfurnaceisremovedfromaventsystem

servingotherappliances,theexistingventsystemmay

notbesizedproperlytoventtheremainingappliances

(example: water heater). An improperly sized venting

systemcanresultintheformationofcondensate,leakage,

orspillage.Theexistingventsystemshouldbechecked

tomakesureitisincompliancewithNFGC and must

bebroughtintocompliancebeforeinstallingthefurnace.

NOTE: Ifreplacinganexistingfurnace,itispossibleyouwill

encounteranexistingplasticventingsystemthatissubject

toaConsumerProductSafetyCommissionrecall.The

pipesinvolvedintherecallareHighTemperaturePlastic

Vent(HTPV).If your venting system contains these

pipesDO NOT reuse this venting system!Thisrecall

doesnotapplytootherplasticventpipes,suchaswhite

PVCorCPVC.CheckfordetailsontheCPSCwebsiteor

calltheirtoll-freenumber(800)758-3688.

Ventilaire III or IV Air Quality Package

TheVentilaireairqualityaccessorypackagesareavailable

tomeettheventilationrequirementsasoutlinedinH.U.D.

StandardPart3280.103(b)(2).Thesepackagesintroduce

outdoorair intothelivingspace duringfurnace blower

operation.TheVentilAireIValsoservestoexhaustmoist

and/orhotairfromtheatticspace.SeeFigure5fortypical

installation.Completeinstallationinstructionsaresupplied

witheachairqualitypackage.

VentilAireIII

VentilAireIV

Figure 5. VentilAire III & IV

VentFreezingProtection

CAUTION:

Whentheventpipeisexposedtotemperatures

below freezing (i.e., when it passes through

unheated spaces, chimneys, etc.) the pipe

must be insulated with 1/2 inch thick sponge

rubberinsulation,Armaex-typeinsulationor

equivalent. Insulating pipe is important to avoid

condensate icing.

• Table3liststhemaximumlengthofuepipethatcan

travelthroughanunconditionedspaceoranexterior

space. The total vent length must not exceed the

lengthsnotedintheTable.ForCanadianinstallations,

pleaserefertotheCanadianInstallationCode(CAN/

CGA-B149.1or2)and/orlocalcodes.

• Forextremelycoldclimatesorforconditionsofshort

furnace cycles (i.e. set back thermostat conditions)

thelast18inchesofventpipecanbereduced.Itis

acceptabletoreducefrom3”to2-1/2”or,3”to2”ifthe

totalventlengthisatleast15feetinlength,andthe

ventlengthiswithintheparametersspeciedinTable

2 (page 8).The restriction should be counted as 3

equivalentfeet.Smallerventpipesarelesssusceptible

tofreezing,butmustnotbeexcessivelyrestrictive..

• To prevent debris or creatures from entering the

combustionsystem,aprotectivescreenmaybeinstalled

overthecombustionairintakeopening.Thescreens

holesizemustbelargeenoughtopreventairrestriction.

Winter Design

Temperature

MaximumFluePipeLength(FEET)

inUnconditioned&ExteriorSpaces

Without Insulation With Insulation*

20 45 70

0 20 70

-20 10 60

*NOTE:Insulationthicknessgreaterthan3/8inch,basedonan

Rvalueof3.5(ftxFxhr)/(BTUxin.)

Table 3. Vent Protection

CIRCULATING AIR REQUIREMENTS

WARNING:

Do not allow combustion products to enter the

circulating air supply. Failure to prevent the

circulation of combustion products into the

living space can create potentially hazardous

conditions including carbon monoxide

poisoning that could result in personal injury

or death.

All supply ducts must be secured to the furnace

with sheet metal screws and adequately sealed.

When supply air is provided through the bottom

of the unit, the joint between the furnace and

the plenum must be air tight.

The surface that the furnace is mounted on must

provide sound physical support of the furnace

with no gaps, cracks or sagging between the

furnace and the ﬂoor or platform.

Supply air ducts must not be connected to

any other heat producing device such as a

ﬁreplace insert, stove, etc. This may result in

re, explosion, carbon monoxide poisoning,

personal injury, or property damage.

Plenums & Air Ducts

Thisunitisdesignedonlyforusewithabottomsupply

duct and must be installed in accordance with the

standards of the National Fire Protection Association

Standard for Installation of Air Conditioning Systems

(NFPA90A),StandardforInstallationofResidenceType

WarmAirHeatingandAirConditioningSystems(NFPA

90B),andallapplicablelocalcodes.NFPApublications

are available by writing to: National Fire Protection

Association,BatterymarchPark,Quincy,ME02269orgoto

www.NFPA.orgontheweb.

• Designtheairductsaccordingtomethodsdescribed

bytheAirConditioningContractorsofAmerica(ACCA).

• Air ducts must be aluminum, tin plate, galvanized

sheetsteel,orotherapprovedmaterialsforoutletor

returnairducts.Snap-LockorPittsburgh-Lockseams

arepreferred.Allothertypesofseamsmustbemade

tighttopreventleakage.

• Itis goodpracticetosealallconnectionsandjoints

with industrial grade sealing tape or liquid sealant.

Requirements for sealing ducts vary from region to

region. Consult with local codes for requirements

specictoyourarea.

• Gaspipingmustnotruninorthroughanyoftheair

ductsystem.

• Hollow spaces used as ducts or plenums for

environmentalairmaycontainmineral-insulatedmetal

sheathedcable,aluminumsheathedcable,electrical

metallic tubing, rigid metal conduit, exible metal

conduit(nottoexceed4ft),ormetal-cladcables.Wiring

materials,xtures,aretobesuitablefortheexpected

ambienttemperaturestowhichtheywillbesubjected.

Wiringmaterialslocatedinthereturnductsystemshall

conformtoArticles300-22oftheNationalElectrical

Code(ANSIC1/NFPA-70).

• All ductwork passing throughunconditioned space

must be properly insulated to minimize duct losses

and prevent condensation. Use insulation with an

outervaporbarrier.Refertolocalcodesforinsulation

materialrequirements

• Airconditioningsystemsmayrequiremoreductregister

andopenlouverareatoobtainnecessaryairow.Use

NORDYNE’s certiduct programto determine proper

ductsizesforairconditioning.

• Noncombustiblepanshavingoneinchupturnedanges

are located beneathopenings ina oor return duct

system.

Supply Air Connections

• Forproperairdistribution,thesupplyductsystemmust

be designed so that the static pressure measured

externaltothefurnacedoesnotexceedthelistedstatic

pressureshownonthefurnaceratingplate.Thesupply

airmustbedeliveredtotheheatedspacebyduct(s)

securedtothefurnacecasing,runningfulllengthand

withoutinterruption.

• Duct system must be designed so that no supply

registersarelocatedinductsystemdirectlybelowthe

furnace.

• Location, size, and number of registers should be

selectedonthebasisofbestairdistributionandoor

planofthehome.Threetypicaldistributionsystems

areshowninFigure6

A Single trunk duct

Dual trunk duct

w/crossover connector

Transition duct

w/branches

Figure 6. Typical Supply Duct Systems

Return Air Connections

• M7furnaceswithmodelnumbersendinginAWorBW

arefactoryconguredforthereturnairtoowthrough

the front louvered door.The return air may also be

attachedtoeithersideofthefurnacecabinetusinga

eldinstalledkit(PN904003).Thelocationandsize

ofthesideandtopreturnairconnectionsareshown

inFigures23&24(pages29&30).Theltersizefor

thesidereturnairis20”x20”x1”.

• ModelnumbersendinginBWTarefactorycongured

forthereturnairtoenterthetopofthefurnace.See

Figure25(page31).NOTE:Fortopreturninstallations,

anexternalorin-wallltermountisrecommended.The

returnductshouldbesizedtoprovideadequateairow

• For oorreturn systems,the manufacturedhousing

manufacturerorinstallershallafxaprominentmarking

onorneartheappliancewhereitiseasilyreadwhenthe

closetdoorisopen.Themarkingshallread:“CAUTION,

HAZARDOFASPHYXIATION.DONOTCOVEROR

RESTRICTFLOORRETURNAIROPENING.”

• Returnairopeningsshouldnotbelocatedtodrawair

directlyfromabathroom.

• Materialslocatedinthereturnductsystemshallhave

aamespreadclassicationof200orless.

• Thetotalfreeareaoftheopeningsintheoororthe

ceilingregistersservingthereturnairductsystemmust

notbenotlessthan352in

(2,270cm

).Atleastone

coveredbycarpeting,boxesandotherobjects.

Closet & Alcove Installations

WARNING:

Failure to comply with the the following

instructionsmayresultinre,asphyxiationor

carbonmonoxidepoisoning.

For proper air circulation, closet installations require

a return air grill installed in the door or side wall that

exchangeswiththelivingareaofthehome.Apartially

louvereddoormayalsobeusedacrosstheopening.Grilles

placedinasidewallrequirea6”clearancefromthewall

tothefurnacesothattheairmayenterthefrontgrille

ofthefurnace.Allreturnairsystems,includingtheoor

andceilingsystems,mustmeetthefollowingconditions:

• Thereturnairopening,regardlessofitslocationinthe

closet,mustnotbesmallerthansizespeciedonunit

datalabel.Iflocatedintheoor,theopeningmustbe

providedwith a meansof preventingits inadvertent

closurebyatobject(s)placedovertheopening.

• Thecross-sectionalareaofthereturnductsystem(in

oororceiling)leadingintotheclosetmustnotbeless

than235in

(1,516cm

CAUTION:

HAZARD OF ASPHYXIATION: Negative pressure

inside the closet, with closet door closed and

the furnace blower operating on high speed,

shall be no more negative than minus 0.05 inch

water column.

• Testthenegativepressureintheclosetwiththeair-

circulatingfanoperatingathighspeedandthecloset

closed.Thenegativepressureintheclosetmustnot

belessthanminus0.05incheswatercolumnwiththe

closetdoorclosedandthefanoperatingathighspeed.

Thenegativepressureistobenomorenegativethan

minus0.05”watercolumnasthisindicatesadirtylter

orarestrictedreturnairsystem.

• Forclosetinstallationwithlessthan6”frontclearance,

butnot less than 1”, alouvereddoor must be used

havingaminimum250in

(1,613cm

)freeareaopening

directlyinlinewithopeningsinthefurnacedoor.For

1”clearancefromfurnace,useafullylouvereddoor

withatleast400in

(2,580cm

)offreeairowarea.

Furnace Filter

WARNING:

Never operate the furnace without a ﬁlter in

place. Accumulating dust in the return air can

build up on internal components, resulting

in loss of efﬁciency, equipment damage, and

possible ﬁre.

• M7RLfurnaceswithAWorBWsufxesaresupplied

withasingleairlterwhenshippedfromthefactory.

Accessingthelterdoesnotrequiretoolsandcanbe

easilyremovedfromtheinsideoftheaccessdoor.The

lterissecuredtothedoorwitharetainingbracket.It

isrecommendedthatthelterbecleanedorreplaced

monthly.Newlybuiltorrecentlyrenovatedhomesmay

requiremorefrequentchanginguntiltheconstruction

dusthasminimized.

• Replacementltersareavailableatmostlocalretailers.

Inspectltersfrequentlyandreplacewhennecessary

withlterofsamedimensionalsize.Filtersdesignedto

removesmallerparticlessuchaspollen,mayrequire

additionalmaintenance.

Dampers

Anautomatedshutoffdamperisrequiredwhenthehome

is air conditioned by a self-contained unit. A damper

is requiredto preventchilled airfrom owing over the

furnaceheatexchanger.Thisdamperisdesignedtot

inthefeederductcavity,directlyunderthefurnace.For

properinstallation,refertotheinstructionsprovidedwith

thedamper.Seereplacementpartslistprovidedonline.

Acoustical Treatments

Damping ducts, exible vibration isolators, or pleated

media-styleltersonthereturnairinletofthefurnace

maybe usedtoreducethetransmissionof equipment

noiseeminatingfromthefurnace.Thesetreatmentscan

produceaquieterinstallation,particularlyintheheated

space.However,theycanincreasethepressuredropin

theductsystem.Caremustbetakentomaintaintheproper

maximumpressureriseacrossthefurnace,temperature

riseandowrate.Thismaymeanincreasingtheductsize

and/orreducingtheblowerspeed.Thesetreatmentsmust

beconstructedandinstalledinaccordancewithNFPAand

SMACNAconstructionstandards.Consultwithlocalcodes

forspecialrequirements.Forbestsoundperformance,

install all the needed gaskets and grommets around

penetrationsintothefurnace,suchasforelectricalwiring.

FURNACE INSTALLATION

NOTE: TheseInstallationproceduresaresuggestedfor

typical furnace installations. Since each installation is

different, the sequence of instructions may differ from

theactualinstallation.OnlyqualiedHVACtechnicians

shouldinstallthisfurnace.

The installer must be familiar withand complywith all

codes and regulations applicable to the installation of

these heating appliances and related equipment. In

theabsenceof local codes,the installation mustbein

accordancewiththecurrentprovisionsofoneormoreof

thefollowingstandards.

• FederalManufacturedHomeConstructions&Safety

Standard(H.U.D.Title24,Part3280.707[a][2])

• AmericanNationalStandard(ANSI-119.2/NFPA-501C)

forallrecreationalvehicleinstallations.

• AmericanNationalStandard(ANSI-Z223.1/NFPA-54)

and/orCAN/CSAB149forallgas-redfurnacemodels.

• American National Standard (ANSI-Z95.1/NFPA-31)

and/orCSAB139foralloil-redfurnacemodels.

• AmericanNationalStandard(ANSI-C1/NFPA-70)and/

or CSA 22.1 Canadian Electric Code Part 1 for all

electricaleldwiring.

• UnitshavebeenresearchedunderstandardsUL307A

&B,UL727-1999,ANSIZ21.47b/CSA2.3b-2008,and

CSAB140.10.

About The Furnace

TheM7RLfurnaceisdesignedonlyforindoorinstallations

and can be readily connected to the high static duct

systemofahome.Unitsareapprovedforsingle/multistory

residentialormobile/modular/manufacturedstructuresin

freestanding/closet/alcovedownowonlycongurations.

This appliance will provide many years of safe and

dependable comfort, providing it is properly installed

andmaintained.Abuse,improperuse,and/orimproper

maintenancecanshortenthelifeoftheapplianceand

createunsafehazards.Pleasereadallinstructionsbefore

installingtheunit.

Approved installation, operation, and maintenance of

this appliance must be in accordance with the listed

specicationscontainedintheseinstructionsandother

documentssuppliedwiththefurnaceand/oroptionalair

conditioningequipment.Unlessitisnoteddifferentlyinthis

manual,onlyusefactoryauthorizedkitsandaccessorieson

thisappliance.Refertolocalauthoritieshavingjurisdiction

forfurtherinformation.

Before You Install this Furnace

√ Thisequipmentis securely packagedatthe time of

shipmentanduponarrivalshouldbecarefullyinspected

fordamagepriortoinstallingtheequipmentatthejob

site.Claimsfordamage(apparentorconcealed)should

beledimmediatelywiththecarrier.

√ Checktheelectricalsupplyandverifythepowersupply

isadequateforunitoperation.Thesystemmustbewired

andprovidedwithcircuitprotectioninaccordancewith

localbuildingcodes.Ifthereisanyquestionconcerning

thepowersupply,contactthelocalpowercompany.

√ Verify theair delivery ofthe furnace isadequate to

handlethestaticpressuredropofthecoil,lter,and

ductwork.

Locating the Unit

• Thedimensionsoftheroomoralcovemustbeableto

accommodatetheoverallsizeoftheunitandrequired

clearancestocombustiblematerialslistedinTable1

(page 5). Access for positioningand servicing must

alsobeconsideredwhenlocatingtheunit.Todetermine

the required clearances needed for installation and

combustiblematerials,refertoFigures23-25(pages

29-31)foroveralldimensions.

• The furnace must be installed on a solid surface

and must be level front-to-back and side-to-side at

installation.Thesurfacethatthefurnaceismounted

onmustprovidesoundphysicalsupportoftheunit.

• Thefurnaceshouldbeinstalledasclosetothecenter

oftheairdistributionsystemaspossibleandattached

toaproperlyinstalledductsystem.Do not use the

back of the furnace for return air. Seepages11-12

forcirculatingrequirements.

• The furnace must be installed so that all electrical

componentsareprotectedfromwater.

• TheplenumattachedtotheA/Ccoilboxandductwork

within 3 ft. of the furnace must be installed so that

surfacesareatleast1/4”fromcombustibleconstruction.

• Wheninstalledinaresidentialgarage,thefurnacemust

be positioned sothe burners and thesource ofthe

ignitionarelocatednolessthan18inchesabovethe

oorandprotectedfromphysicaldamagebyvehicles.

• Thisfurnace is certiedforuseonwoodooringor

supports,butmustnotbeinstalleddirectlyoncarpeting,

tile,oranycombustiblematerialotherthanwoodooring.

NOTE:Thefurnacemaybeinstalledoncombustible

ooringwheninstalledonaNordyneductconnector

(Figure7).This factory supplied accessory must be

installedintheoorcavityandattachedtothesupply

airductbeforethedownowfurnaceisinstalled.

• The furnace must be installed upstream from a

refrigerationsystem.

NOTES:

With reducer installed: Opening to duct is 10-1/4” x 13-1/4”.

With reducer removed: Opening to duct is 13-1/4” x 13-1/4”.

REDUCER

(See Notes)

FELT-SEAL

SPACERS

DUCT CONNECTOR TABS

FIBERGLASS

INSULATION

Figure 7. Duct Connector

14 1/2”

Floor Cut-Out for

Duct Connector

FURNACE CABINET OUTLINE

Optional floor cutouts for gas,

condensate, or AC linesets

(3 1/2 x 1 1/2 - 2 places)

21 5/8

TYP.

1/2 TYP.

REAR WALL OF CLOSET OR ALCOVE

2 1/4

16 3/4

Furnace Door

1 1/2 TYP.

20"

2 3/4

Figure 8. Floor Cutout Dimensions

CEILING CUT-OUTS FOR

VENT & COMBUSTION AIR

20"

23 3/4"

REAR WALL OF CLOSET OR ALCOVE

FURNACE

OUTER

DOOR

FURNACE OUTLINE

21 7/8

2 1/2

2 3/4

COMBUSTION

AIR INLET

EXHAUST

VENT

Figure9.CeilingCut-OutDimensions

“X”

FLOOR OPENING

FLOOR

CAVITY

SUPPLY AIR DUCT

If Floor Cavity

(“X”) is:

Duct Connector

Type & Part Number

Finger Tab Screw Down

7/8”(22) 901987A 904008

2”(51) 901988A 904009

4-1/4”(108) 901989A 904010

6-1/4”(159) 901990A 904011

8-1/4”(210) 901991A 904012

10-1/4”(260) 901992A 904013

12-1/4”(311) 901993A 904014

NOTE:DimensionsshownasInches(Millimeter)

Table 4. Duct Connector Sizes

Locating&CuttingFloorOpenings

IMPORTANT NOTE: Cut-outs in the oor, must be

carefully located to avoid misalignment of the furnace.

Tolocatestandardducts,seeFigure8.Forroundducts,

seeFigure9.

1. Measurefromthe rear wall or alcoveand markthe

centerlineofthecut-outontheoor.Usingthecenterline

asastartingpoint,drawtherestoftheductcut-outto

thedimensionsshowninFigure8.

2. Cutouttheooropeningtowithin1”oftheactualcutout

drawn.

3. Measurefromthetopoftheoordowntothetopofthe

supplyairducttoobtainthedepthoftheoorcavity.

NOTE: Thedepthoftheoorcavityshownas“X”in

Table4willdeterminethecorrectductconnector.

4. Determinewhichductconnectortousefromthetable.

6. Measureanddrillgasholeandcutoutforcoolingcoil

(ifapplicable).SeeFigures8or9.

Locating&CuttingCeilingOpenings

IMPORTANTNOTE:Cut-outsintheceilingandroof

must be carefully located to avoid misalignment of

the furnace, combustion air piping, and vent piping.

See Figure 9.

1. Measurefromthe rear wall or alcoveand markthe

centerlinesofbothcut-outsintheceiling.

2. Usingthecenterlinesasastartingpoint,drawtherest

ofthecut-outstothedimensionsshowninFigure9.

3. Cutouttheceilingopenings.

Installing Finger Tabbed Duct Connectors

Thestandardductconnectorisdesignedforuseonducts

12”inwidth.Howeverductsnarrowerthan12”maynot

allowsufcientclearancesforthistypeofinstallation.For

analternateinstallationmethod,seepage15.

1. Centerthe duct connectorin theoor openingwith

bottomtabsrestingontopofthesupplyairduct.

2. Markthecut-outareaonthesupplyairductbytracing

aroundtheconnectortabs(Figure10,page15)ofthe

ductconnector.

3. Removetheductconnectorandcutoutthemarked

areaofthesupplyairduct1/16”largertheactualcutout

drawn.

4. Installtheductconnectorbackintheooropeningwith

thebottomtabsextendingintothesupplyairduct.

5. Installthemountingplate(Figure10)undertheback

sideoftheductconnector.Alignthescrewholes in

bothcomponents.

6. Securetheductconnectorandthemountingplateto

thewoodoorwithappropriatesizescrews.

Tabs slide into slots

in back of furnace

Mounting

Plate

Duct

Connector

Supply

Air Duct

Hole for

Gas Line

Wood Floor

Connector

Tabs

Duct Connector

Supply

Air Duct

Bend tabs tightly

against supply air duct

Figure 10. Finger Tabbed Duct Connector

Tabs slide into slots

in back of furnace

Mounting

Plate

Screw Down

Duct Connector

Supply

Air Duct

Hole for

Gas Line

Wood Floor

Figure13.Screw-DownDuctConnector

7. Bend the connector tabs on the bottom of the duct

connectorupwardsand as tightaspossibleagainst

thesupplyairduct.SeeFigure11(page15).

8. Sealallconnectionswithindustrialgradesealingtape

or liquid sealant. NOTE: Requirements for sealing

ductworkvaryfromregiontoregion.Consultwithlocal

codesforrequirementsspecictoyourarea.

NarrowDuctAttachment-Option1

Thesalternateattachmentmethodsmaybeusedtoinstall

a furnace duct connector to narrow metal ductwork if

insufcientclearancespreventthebendingoftheduct

connectortabsatthesideoftheduct.

1. SelectOptionAorOptionBinFigure11andcutthe

topofthesupplyairduct.Removemetalapsfromthe

duct(shadedarea)ifOptionAisselected.

2. Foldtheductapsuptoformanopeningfortheduct

connector(appliestoOptionsAorB).

3. Installtheductconnectorwiththebottomtabsextending

intothesupplyairduct.

4. Bend the tabs on the bottom of the duct connector

upwardsandastightaspossibleagainsttheremoved

endsofthesupplyairduct.

5. Form theduct aps upagainst theside of theduct

connectorastightaspossible.SeeFigure11.

6. Securetheductconnectorapstothesupplyairduct

withstaples(3minimum)orifa2xblock/joistisnot

provided,usesheetmetalscrews(2minimum).

NOTE:The ductconnectortabsmaybe attachedto

theairductwithsheetmetalscrewsorothersuitable

fastenersaslongastheductconnectorandtheairduct

aresecurelyattached.

7. Sealallconnectionswithindustrialgradesealingtape

orliquidsealant.

NOTE: Requirements for sealing ductwork vary

from region to region. Consult with local codes for

requirementsspecictoyourarea.

NarrowDuctAttachment-Option2

Thesalternateattachmentmethodsmaybeusedtoinstall

a furnace duct connector to narrow metal ductwork if

insufcientclearancespreventthebendingoftheduct

connectortabsatthesideoftheduct.

1. Cutandremovethetopofthesupplyairductasshown

inFigure12.

2. Installtheductconnectorwiththebottomtabsextending

intothesupplyairduct.

3. Bend the tabs on the bottom of the duct connector

upwardsandastightaspossibleagainstthesupply

airduct(Figure12).

4. Securetheductconnectortabstothesupplyairduct

with staples (3 minimum) or sheet metal screws (2

minimum).

Figure11.NarrowAirDucts-Option1

Cutting

Option A

Supply

Air Duct

Fold duct flap here

Remove

this Flap

Cut Here

Fold Flap Here

Narrow

Duct

Narrow

Duct

Finger Tabs

Secure Flaps with Staples

or sheet metal screws

Fold duct flaps

into duct

connector

Remove

this Flap

Fold Flap Here

Cutting

Option B

Fold duct flap here

Supply

Air Duct

Narrow

Duct

Finger Tabbed

Duct Connector

Secure finger tabs to

side of air duct with staples

or sheet metal screws

Bend tabs tightly

against supply air duct

Supply Air Duct

Cut out & remove

Figure12.NarrowDucts-Option2

Figure 14. Round Duct Connector

Tabs slide into slots

in back of furnace

Mounting

Plate

14” Round

Duct Connector

Optional Hole

for Gas Line

Optional Hole

for Gas Line

InstallingScrew-DownDuctConnectors

1. Applyabeadofcaulking,mastic,orotherapproved

sealantaroundbottomsideof1/2”angeandrestrictor

plate(whenapplicable).

2. Locatethescrewdownductconnectorovertheduct

andcarefullyloweritintoplace.

3. Securetheductconnectortotheoorusingathead

screwsornails.NOTE:Makesuretheductconnector

angesstayincontactwiththeduct.

4. Securetheplenumtotheductusingsheetmetalscrews

makingsureatightsealismadebetweentheductand

theductconnector.NOTE:Additionalscrewsmaybe

addedifrequired.

5. Cutawayalongedgeofangeallowingthecenterto

dropintotheduct.NOTE:Removesectionofductwith

caution,asedgeswillbesharp.

Round Duct Connector Installation

1. Installandcentertheductconnectorintheooropening.

2. Installthemountingplate(Figure14,page16)under

thebacksideoftheductconnector.NOTE:Makesure

thescrewholesarealignedinbothcomponents.

3. Using appropriate size screws, secure the duct

connectorandthemountingplatetothewoodoor.

4. Connecttheroundsupplyducttotheundersideofthe

duct connectorand securethem witheld supplied

sheetmetalscrewsorappropriateclamps.

5. Sealallconnectionswithindustrialgradesealingtape

orliquidsealantasrequired.

NOTE: Requirements for sealing ductwork vary

from region to region. Consult with local codes for

requirementsspecictoyourarea.

Installing the Furnace

Sidesandbackofthefurnacemaybeenclosedbywall

framingsuchasinaclosetoralcove.Thedimensionsof

theroom or alcovemust be ableto accommodate the

overallsizeofthefurnaceandtheinstallationclearances

outlinedonpage5andFigures1-4(page6).Thefurnace

shallbeappropriatelyconnectedtothesupplyandreturn

airdistributionsystemasshowninFigures23-25(pages

29-31).

1. Remove furnace outer door(s) and bottom fuel line

knockout.

2. Placefurnaceontoductconnectorandcenterwithoor

opening.

3. Slideontomountingplate.(Bottomrearslotsonfurnace

shouldengagewithmountingplatetabs.)

4. Secure front with one (1) fastener at each corner

(Figures14or15).

NOTE:Additionalfastenersmaybeusedatrear,sides

orthroughdoorframe,asdesired,tosecurefurnaceto

closetoralcoveframing.

Condensate Drainage

WARNING:

The condensate produced by the furnace must

be drained. Do not connect a water supply to

the drainage hose of the furnace.

NOTE:Thecondensatedrainshouldbeprotectedfrom

freezingwheninunheatedspaces.Thefurnaceissupplied

withaninternalcondensatedraintrap.

CAUTION:

Do not install additional traps in the condensate

drain.

Thecondensatedrainmayexitthroughtheleftorright

slotsinthebottomofthefurnace(Figure16).Makesure

theexibledrainhoseisnotkinked.

Thecondensateshoulddrainfromtheplasticcollectorbox

asdropletsorasmallstream.Ifyounoticethefurnace

hasoperatedformorethan5minuteswithoutdraining

ortheredstatuslightonthecontrolboardispulsinga

2-blinkcodefollowthestepsbelow.

1. Remove the collectorbox soft tube(Figure16) and

verify the exit from the collector box is clear of any

debrisorobstructions.

2.Replacethistubeandverifythettotheheaderspout

is air tight. Air will be drawn into the header if this

connectionisnottight.

3.Checkothertubeconnectionsalongthedrainsystem.

Verifythatallareairtight.

Figure 16. Condensate Drainage

B Cabinets

Tall & Top Return Air Type

Short A Cabinet

Optional Exits for

Condensate Drain Lines

Collector

Box Drain

Inline

Drain

Optional Exits for

Condensate Drain Lines

MTG. PLATE TABS

SLIDE FURNACE

ALL THE WAY BACK

ONTO MTG. PLATE

SUPPLY AIR DUCT

Knockout Over Holes

SECURE FURNACE WITH

2 FASTENERS IN FRONT

Figure 15. Cabinet Furnace on Supply Air Duct

FIRE OR EXPLOSION HAZARD

•Failuretofollowsafetywarningsexactly

could result in serious injury or property

damage.

•Installationandservicemustbeperformed

by a qualiﬁed installer, service agency or

the gas supplier.

• Donotstoreorusegasolineorother

ﬂammable vapors and liquids in the

vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS

•Donottrytolightanyappliance.

•Donottouchanyelectricalswitch;donot

use any phone in your building.

•Leavethebuildingimmediately.

•Immediatelycallyourgassupplierfrom

a neighbor’s phone. Follow the gas

supplier’s instructions.

•Ifyoucannotreachyourgassupplier,call

the ﬁre department.

WARNING:

RISQUE D’INCENDIE OU D’ EXPLOSION

• Lenon-respectdesavertissementsdesécurité

pourrait entraîner des blessures graves, la mort

ou des dommages matériels.

• L’installationetl’entretiendoiventêtreeffectués

par un installateur qualiﬁé, un organisme de

service ou le fournisseur de gazstaller, service

agency or the gas supplier.

• Ne pas entreposer ni utiliser de l’essence ni

d’autres vapeurs ou liquides inﬂammables dans le

voisinage de cet appareil, ni de tout autre appareil.

QUE FAIRE S’IL Y A UNE ODEUR DE GAZ

• Nepastenterd’allumeraucunappareil.

• Ne toucher à aucun interrupteur électrique;

n’utiliser aucun téléphone dans le bâtiment.

• Évacuerl’immeubleimmédiatement.

• Appelerimmédiatementlefournisseurdegazen

employantletéléphoned’unvoisin.Respecterà

la lettre les instructions du fournisseur de gaz.

• Sipersonnenerépond,appelerleservicedes

incendies.

AVERTISSEMENT:

GAS SUPPLY & PIPING

• All gas piping must be installed in compliance with

local codes and utility regulations. In the absence

of local codes the gas line installation must comply

with the latest edition of the Federal Manufactured

Home Constructions & Safety Standard (H.U.D. Title

24, Part 3280.707[a][2]), National Fuel Gas Code

(ANSI Z223.1) or (CAN/CGA B149.1 or .2) Installation

Codes.

• Some local regulations require the installation

ofamanualmainshut-offvalveandgroundjoint

unionexternaltothefurnaceasshowninFigure17

(page 18).The shut-off valve should be readily

accessible for service and/or emergency use.

Consult the local utility or gas supplier for additional

requirements regarding placement of the manual

maingasshut-off.

• Gaspipingmustneverruninorthroughairducts,

chimneys, gas vents, or elevator shafts.

• Compoundsusedonthreadedjointsofgaspiping

must be resistant to the actions of LP propane gas.

• Themaingasvalveandmainpowerdisconnectto

the furnace must be properly labeled by the installer

in case emergency shutdown is required.

• Flexiblegasconnectorsarenotrecommendedfor

this type of furnace but may be used if allowed by

local jurisdiction. Only new exible connectors

may be used. Do not use a connector which has

previously serviced another gas appliance.

• Adriplegshouldbeinstalledintheverticalpipe

run to the unit if not entering the furnace through

the ﬂoor.

Table9(page33)listsgasowcapacitiesforstandard

pipesizesasafunctionoflengthintypicalapplications

basedonnominalpressuredropintheline.

Thefurnaceisinstalledwithabottomgasentry.When

connectingthegassupply,provideclearancebetweenthe

gassupplylineandtheentryholeinthefurnacecasing

toavoidunwantednoiseand/ordamagetothefurnace.

TypicalgashookupsareshowninFigure17.

FIRE OR EXPLOSION HAZARD

Failuretofollowsafetywarningsexactlycould

result in serious injury or property damage.

Never test for gas leaks with an open ﬂame.

Use a commercially available soap solution

made speciﬁcally for the detection of leaks

tocheckallconnections.Areorexplosion

may result causing property damage, personal

injury or loss of life.

WARNING:

RISQUE D’INDENDIE OU D’EXPLOSION

Le non-respect des avertissements de

sécurité pourrait d’entraîner des blessures

graves, la mort ou des dommages matériels.

Ne jamais utiliser une ﬂamme nue por vériﬁer la

présence des fuites de gaz. Pour la vériﬁcation

de tous les joints, utiliser plutôt une solution

savonneuse commerciale fabriquée spéciﬁquement

pur la détection des fuites de gaz. Un incendie ou

une explosion peut entraîner des dommages

matériels, des blessures ou la mort.

AVERTISSEMENT:

Shut-Off

Valve

Elbows

Gas Valve

Shut-Off

Valve

Elbows

A Cabinet (Short)

B Cabinets

(Tall & Top Return Air Type)

Alternate Fuel

Line Entrance

Alternate Fuel

Line Entrance

Alternate Fuel

Line Entrance

Figure 17. Typical Gas Connections

Leak Check

After the gas piping to the furnace is complete, all

connectionsmustbetestedforgasleaks.Thisincludes

pipeconnectionsatthemaingasvalve,emergencyshutoff

valveandexiblegasconnectors(ifapplicable).Thesoap

andwatersolutioncanbeappliedoneachjointorunion

using a small paintbrush. If any bubbling is observed,

the connection is not sealed adequately and must be

retightened.Repeatthetighteningandsoapcheckprocess

untilbubblingceases.

IMPORTANT NOTE: When pressure testing gas supply

lines at pressures greater than 1/2 psig (14 inch W.C.),

the gas supply piping system must be disconnected

from the furnace to prevent damage to the gas control

valve. If the test pressure is less than or equal to 1/2

psig(14inchW.C.),closethemanualshut-offvalve.

High Altitude Application

High altitudeconversion with thisfurnace depends on

theinstallationaltitudeandtheheatingvalueofthegas.

Installationofthisfurnaceataltitudesabove2,000feet

shallbeinaccordancewithlocalcodes,orintheabsence

oflocalcodes,theNationalFuelGasCode,ANSIZ223.1/

NFPA54orNationalStandardofCanada,NaturalGas&

PropaneInstallationCodeCGAB149.1.Pleaseconsult

yourlocalcodeauthority.

WARNING:

The reduction of input rating necessary for high

altitude installation may only be accomplished

with factory supplied oriﬁces. Do not attempt to

drill out oriﬁces in the ﬁeld. Improperly drilled

orices may cause re, explosion, carbon

monoxidepoisoning,personalinjuryordeath.

Thefurnacesareshippedfromthefactorywithorices

andgasregulatorsettingsfornaturalgasoperationatsea

levelaltitudes.At2000feet,theNFGCrequiresthatthis

appliancebederated4%foreach1000feetofaltitude.

Forexample,theinputneedstobereduced8%at2,000

feet,12%at3,000feet,etc.Thisderationisinreference

totheinputrateandgasheatingvalueatsealevel.

Toderatethefurnacerequiresknowingtheheatingvalueof

thegasattheinstallationsite.Heatingvaluesatparticular

jobsitesvaryfortworeasons:

1.Thechemicalmixtureofthegasvariesacrossregions

andisexpressedasthe“sealevelheatingvalue”.

2.Theheatingvaluevariesbyaltitude.Forthisreason,

especially in high altitude areas, the local gas utility

speciestheheatingvalueattheresidence’sgasmeter

asthe“localvalue”.

Foraddedexibility,twotableshavebeenprovidedfor

naturalgasinstallationswithhighorlowheatingvaluesat

sealevel.Tables12&13(page34)containthemanifold

pressure and orice sizes to use at various altitudes.

Table 12 (HIGH) is for natural gas installations with a

heatingvalueofmorethan1,000Btupercubicfootand

Table13(LOW)isforlessthan1,000Btupercubicfoot.

Todeterminewhichtabletouse:

1.Consultthelocalutilityforthelocalheatingvalueat

yourinstallationsite.

2.FromTable11(page34),ndyourlocalheatingvalue

as supplied by the utility company. Follow down the

columnandstopatyouraltitudelevel.

3.IfyoursealevelheatingvalueisHIGH,useTable12or

ifit’sLOW,useTable13.Seeexample.

Afterchangingtheregulatorpressureortheorices,itis

requiredthatyoumeasurethegasinputrate.Thismaybe

accomplishedintheusualway,byclockingthegasmeter

Converting to LP/Propane Gas at Altitudes

between 0 & 10,000 FT.

WARNING:

The furnace was shipped from the factory

equipped to operate on natural gas. Conversion

to LP / Propane gas must be performed by

qualiﬁed service personnel using a factory

supplied conversion kit. Failure to use the

properconversionkitcancausere,explosion,

propertydamage,carbonmonoxidepoisoning,

personal injury, or death.

ConvertingsinglestagevalvestoLP/Propanerequires

thereplacementof the burnerorices and ippingthe

regulatorcaptothesidemarkedLP.Theendfacingup

shouldnowreadLP.SeeFigure18.

InstallationExample

Elevation:.................................................. 5,000feet

Type of Gas:........................................... NaturalGas

Local Heating Value of Gas:..............................750

FromTable11,nd750andfollowdownthecolumn,

stopatthe5,000feetrow.Theheatingvaluelistedis

LOW.Table13willbeusedtodetermineoricesizeand

manifoldpressure.

andusingthelocalgasheatingvalue.SeeVerifyingand

AdjustingtheInputRatesection(page24).

IMPORTANT NOTE: Observe the action of the burners

to make sure there is no yellowing, lifting or ﬂashback

of the ﬂame.

Inlet

Pressure

Ta p

Manifold

Pressure Ta p

On / Off Knob

Te rminal

Connectors

OTHER SIDE

OF CAP

Adjusting Screw

Regulator Cap

Figure 18. Gas Valve

Table10(page34),providesthemanifoldpressurefor

altitudesabove2,000feet.

WARNING:

Shut off the gas supply at the manual gas shutoff

valve, before disconnecting the electrical power.

Areorexplosionmayresultcausingproperty

damage, personal injury or loss of life. Failure to

followthesafetywarningsexactlycouldresult

in serious injury, death or property damage.

WARNING:

To avoid electric shock, personal injury, or death,

turn off the electric power at the disconnect

or the main service panel before making any

electrical connections.

WARNING:

The reduction of input rating necessary for high

altitude installation may only be accomplished

with factory supplied oriﬁces. Do not attempt to

drill out oriﬁces in the ﬁeld. Improperly drilled

orices may cause re, explosion, carbon

monoxidepoisoning,personalinjuryordeath.

RemovingTheBurnerOrices

1.SetthethermostattotheOFFposition,oritslowest

temperaturesetting.

2.ShutOFFthegassupplyatthemanualshutoffvalve

locatedoutsideoftheappliance.

3.Turnoffallelectricalpowertotheappliance.

4.Removethedoorfromtheburnerboxbyremoving6

screws.

5.TurnthegasvalveON/OFFknobtotheOFFposition.

SeeFigure18.

6.Removethewiresfromtheterminalsofthegasvalve.

7.Removethesupplygaspipingfromthegasvalveinlet.

8.Carefullyremovefourscrewssecuringthegasmanifold

assemblytotheburnerassembly.SeeFigure19(page

20).

9.Set the screws aside and remove the gas manifold

assemblyfromtheappliance.

10.Carefully remove the burner orices from the gas

manifoldassembly.

11.Read the rating plate afxed to the appliance to

determineitsratedinput(Btu/hr)andthesizeofthe

factoryinstalledorices.

 IMPORTANT: Before installing an oriﬁce, check

the side or face of the oriﬁce for the drill number

to ensure that it is the appropriate size.

12.InstalltheappropriateLP/Propanegasburnerorices

intothegasmanifoldassembly.NOTE:Theoricesare

includedwiththefurnace. Topreventcrossthreading,

handtightentheoricesintothegasmanifoldassembly

untilsnug,thentightenwithawrench.

13.Unscrewthegasvalvepressureregulatorcapmarked

NAT.InvertthecapsoLPfacesup.Reinstallthecap

andtightenuntilsnug.MakesureLPisvisibleafter

conversion.

WARNING:

Do not use Teﬂon tape or pipe joint compound

on the oriﬁce threads. The hole in the oriﬁce

maybecomeblockedandcausere,explosion,

propertydamage,carbonmonoxidepoisoning,

personal injury, or death.

14.Reinstall the gas manifold assembly to the burner

assemblywiththe4screws,thatwereremovedearlier.

NOTE:Itisimportantthatthecenteroftheorices

arealignedwiththecenteroftheburners.

15.Reinstalltheburnerboxdoorwiththe6screwsthat

wereremovedearlierinstep4.

16.Reconnectthegaspipingtothegasvalveinlet.

17.Reconnectthewirestothegasvalveterminals.

Gas Pressure Adjustment

MeasuringtheSupplyGasPressure

1.TurnOFFthegassupplyatthemanualvalvelocated

ontheoutsideoftheunit.

2.Usinga3/16”Allenwrench,removetheplugfromthe

inletpressuretap(INLETsideofgasvalve).SeeFigure

18(page19).

3.Installan1/8”NPTpipethreadtting,thatiscompatible

withaManometerorsimilarpressuregauge.

4.ConnecttheManometerorpressuregaugetotheInlet

PressureTap.

5.TurnONthemaingassupplyatthemanualvalve.

6.Checkand adjust theincoming gasline pressureto

11.0-14.0inchesWaterColumnforLP/Propanegas.

7.TurnOFFthegassupplyatthemanualvalve.

8.DisconnecttheManometerorpressuregauge.

Figure 19. Oriﬁce Removal

Burner Box

Orifice

(X4)

Gas Valve

Gas Manifold

Burner Box

Door

(X4)

(X6)

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Miller M7RL Series, M7RL Installation guide

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