Broan M7RL Series Installation guide

Two-Stage, Direct Vent (Sealed Combustion)

Forced Air

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 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 NORDYNE

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 qualié, 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

• ModularHomes/Buildings

• ParkModels,&Manufactured

Buildings

M7TL Series Downﬂow Condensing Gas Furnace 95+ % AFUE

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

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

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

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

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

HeatingLoad............................................................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................................................................. 13

AcousticalTreatments............................................ 13

FURNACE INSTALLATION ....................................... 14

AbouttheFurnace.................................................. 14

BeforeYouInstallthisFurnace............................... 14

LocatingtheUnit.................................................... 14

Locating&CuttingFloorOpenings...................... 15

Locating&CuttingCeilingOpenings.................... 15

InstallingFingerTabbedDuctConnectors............. 15

NarrowDuctAttachment-Option1...................... 16

NarrowDuctAttachment-Option2...................... 16

InstallingScrew-DownDuctConnectors................ 17

InstallingRoundDuctConnectors.......................... 17

InstallingtheFurnace............................................. 17

CondensateDrainage............................................ 17

GAS SUPPLY & PIPING ............................................ 18

LeakCheck........................................................... 19

High-AltitudeApplication........................................ 20

ConvertingtoLP/PropaneGas............................ 20

ELECTRICAL WIRING ............................................... 21

LineVoltageWiring................................................ 21

Grounding............................................................... 22

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

HeatAnticipator.................................................... 22

SingleStageAC&SingleStageT-Stat................ 22

SingleStageAC&TwoStageT-Stat.................... 22

AutostagingforSingleStageT-Stats..................... 22

AutostagingforTwoStageT-Stats......................... 23

VariableSpeedBlower......................................... 23

START-UP & ADJUSTMENTS ................................... 23

Pre-StartChecklist................................................. 23

Start-UpProcedures.............................................. 23

Verifying&AdjustingInputRate............................. 23

VerifyingTemperatureRise.................................... 24

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

VerifyingOperationoftheSupplyAir

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

OPERATING SEQUENCE ......................................... 25

HeatingCycle......................................................... 25

CoolingCycle......................................................... 25

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

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

TROUBLESHOOTING ............................................... 27

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

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

Figure23-BWSeriesDimensions...................... 29

Figure24-BWTSeriesDimensions.................... 30

AirowData............................................................ 31

Table6-

NominalCooling/HeatPumpCFM-

VariableSpeed................................... 31

Table7-

NominalHeating(CFM)&

TemperatureRises

.............................. 31

ElectricalDiagrams&Data.................................... 32

Table8-WireLength&VoltageSpecications.... 32

Figure25-LineVoltageFieldWiring.................... 32

Figure26-M7TLMotorControlBoard................ 32

Figure27-M7TLFurnaceControlBoard............ 32

Figure28-M7TLWiringDiagram........................ 33

GasInformation...................................................... 34

Table9-GasFlowRates..................................... 34

Table10-GasPipeCapacities............................ 34

Table11-LiquidPropaneConversionChart........ 35

Table12-Natural

GasHeatingValues.................35

Table13-HighAltitudeDerationforNat.Gas-

HighHeatingValues............................ 35

Table14-HighAltitudeDerationforNat.Gas-

LowHeatingValues............................. 35

VentingInformation................................................ 36

Table15-VentTerminationClearances............... 36

Figure29-Horizontal&VerticalVenting.............. 37

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28(page

33).

• 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 (NFPA 70) 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(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5.

• 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page19.

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

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

ConsultTable7(page31)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

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.

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.

RIGHT

SIDE

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-ﬁred 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 déciente,

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.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. If 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

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

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

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.)

M7TL INPUTS

(BTU)

INLET / OUTLET

2” Diameter

INLET / OUTLET

3” Diameter

45,000 30 60

60,000 30 60

72,000 30 60

†

NOTES:

1. Subtract2.5ft.foreachadditional2inchlongradiuselbow,subtract

5ftforeachadditional2”shortradiiouselbow,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

• 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

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.

• 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

Figures1,2&4(page9)andFigure29(page37).

• 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

(Figure29)alongtheventpipe,oneithersideofthe

exteriorwall.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to4(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14

(page36)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15(page36).

• All minimum clearances (Figure 2, page 9) must

be maintained to protect building materials from

degradationbyuegases.

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.

• In the absence of local codes, the location of any

combustionairinletrelativetoanyventterminalmust

beatleast8inches.Thisincludesinstallationsinvolving

morethanonefurnace.

• 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(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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24(page30).

 NOTE:Fortopreturninstallations,anexternalorin-

wallltermountcanbeused.Thefactoryinstalledlter

shouldberemovedand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.

• M7TLfurnaceswithBWsufxesaresuppliedwitha

singlereusable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.

• M7TLfurnaceswithBWTsufxesareshippedwitha

non-reusablesingle18”x18”x1”airlterfromthefactory.

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

easilyremovedfrominsidetheblowercompartment.

ThelterissecuredwithaU-shaped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.

1. Slidethestandard18”x18”x1”lter(NORDYNEP/N

669779)intothespacebewteenthecombustionair

pipeandtheblowerassembly.SeeFigure7(page

13).NOTE:Makesuretheairowarrowsonthe

lterpointtowardstheblowerassembly.

2. Pushtheltertotherearofthefurnacecabinetand

angleitupovertheblower.Makesurethelteris

pushedbackasfaraspossible.

3. Positionthelterretainerunderthelterandinsert

thesteppedendsintothe0.25holesintherearof

thefurnace.NOTE:Thesteppedendsshouldbe

facingupwardsintheholes.

4. Evenlyalignthelterovertheopeninginthetop

ofthefurnacecabinetandpositiontheotherend

oflterretainerupovertheangeinthefurnace’s

toppanel.NOTE:Toproperlysecurethelter,make

surethelterretainerisproperlypositionedinthe

toppanelofthefurnace.Thereshouldbenovisible

airgaps.Theretainermayslideleftorrightslightly,

butmustnothaveanymovementbetweenthefront

andrear.SeeFigure7.

• 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.

Combustion Air Pipe

Blower

Assembly

Insert filter between

blower assembly &

combustion air pipe

Blower

Assembly

Angle the filter into place

above the blower assembly

Combustion Air Pipe

Filter

Blower

Assembly

Combustion Air Pipe

Align the filter

over the opening and

secure with filter retainer

Filter

Blower

Assembly

Figure 7. Filter Installation

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 (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M7TL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&24(pages

29&30)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-13

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8).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 8. 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 9. 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 10. 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 ﬂoor, must be

carefully located to avoid misalignment of the furnace.

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9.

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).

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 10.

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10.

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 NarrowDuct

Attachment-Options1or2onpage16.

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11,page16)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11)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.

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.

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.

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 11. Finger Tabbed Duct Connector

NarrowDuctAttachment-Option1

Thisalternateattachmentmethod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12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12.

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

Thisalternateattachmentmethod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13.

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13).

Figure 12. 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 13. Narrow Ducts - Option 2

4.Securetheductconnectortabstothesupplyairduct

with staples (3 minimum) or sheet metal screws (2

minimum).

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).SeeFigure14

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15,page17)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.

Figure 15. 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

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9).Thefurnaceshall

beappropriatelyconnectedtothesupplyandreturnair

distributionsystemasshowninFigures23&24(pages

29&30).

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(Figure

16).

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.

CAUTION:

Do not install additional traps in the condensate

drain.

• If the furnace is installed in an area where

temperatures fall below freezing, special precautions

must be made for insulating condensate drain lines

that drain to the outdoors. If condensate freezes

in the lines, this will cause improper operation or

damage to the furnace. It is recommended that

all drain lines on the outside of the residence be

wrapped with an industry approved insulation or

material allowed by local code.

• Beforeroutingthedraintubeoutofthefurnace,loosen

thetubeclampandturnthetubesothepreset90°turn

facestheintendeddirectionofexitfromthecabinet.Do

notroutethedraintubewithoutrotatingthetuberst.

Thiswillkinkthetubeandpreventcondensatefrom

draining.

• Careshouldbetakentoroutethedrainlineawayfrom

theburnerbox.Drainlinesrestingontheburnerbox

canbecomekinkedorcollapsedduetotheheatfrom

theburnerbox.

• Thecondensatedrainmayexitthroughtheleftorright

slotsinthebottomofthefurnace(Figure17,page18).

Makesuretheexibledrainhoseisnotkinked.

Tabs slide into slots

in back of furnace

Mounting

Plate

Screw Down

Duct Connector

Supply

Air Duct

Hole for

Gas Line

Wood Floor

Figure 14. Screw-Down Duct Connector

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 16. Cabinet Furnace on Supply Air Duct

Figure 17. Condensate Drainage

J-Trap

Drain Pipe Routed

thru Slot in Cabinet

To External Drain

Inline Drain

Assembly

Collector

Box Drain

Collector

Box Drain

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 qualié, 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

• 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statuslightsonthecontrolboardindicate

anopenpressureswitchaslistedinTable5(page27),

followthestepsbelow.

1.Removethecollectorboxsofttube(Figure17)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.

• 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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.

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

vérierlaprésencedesfuitesdegaz.Pour

la vérication de tous les joints, utiliser

plutôt une solution savonneuse commerciale

fabriquéespéciquement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

Alternate Fuel

Line Entrance

M7TL BW Model Shown

GROUND

SENSOR

DHUM_IN

Y1_IN

H_OUT

L2-OUT

L2-IN

L1-IN

L1-OUT

Y1_OUT

Y/Y2_OUT

W_OUT

EXPANSION PORT

RED

GREEN

CONNECTION TO

FURNACE CONTROL

BOARD

MOTOR WIRING

HARNESS

RED

INPUT TERMINALS

COOL

HEAT

FAN SPEED

OUTPUT TERMINALS

STATUS LIGHTS

12 3

56 7

OFF ON

Figure 18. Typical Gas Connections

Table10(page34)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18.

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.

The installer must indicate the furnace has been

converted to high altitude. This may be accomplished

by marking the rating plate with a permanent marker.

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13&14(page35)containthemanifold

pressure and orice sizes to use at various altitudes.

Table 13 (HIGH) is for natural gas installations with a

heatingvalueofmorethan1,000Btupercubicfootand

Table14(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12(page35),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13or

ifit’sLOW,useTable14.Seeexampleabove.

Converting to LP/Propane Gas at Altitudes

between 0 & 10,000 FT.

Convertingtwo-stagefurnacestoLP/Propanerequires

thereplacementoftheburneroricesandconvertingthe

regulatortoLP.

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.

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.

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14willbeusedtodetermineoricesizeand

manifoldpressure.

Afterchanging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andusingthelocalgas

heatingvalue.SeeVerifying&AdjustingtheInputRate

section(pages23-24).

IMPORTANT NOTE: Observe the action of the burners

to make sure there is no yellowing, lifting or ﬂashback

of the ﬂame.

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Broan M7RL Series, M7TL Installation guide

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