Unbranded M7RL Series Installation guide

Category
Fireplaces
Type
Installation guide

This manual is also suitable for

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
• ModularHomes/Buildings
• ParkModels,&Manufactured
Buildings
2
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................................................................. 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
RemovingtheBurnerOrices.............................. 21
GasPressureAdjustment...................................... 21
MeasuringtheSupplyGasPressure.................... 21
Lighting&AdjustmentoftheAppliance................ 22
MeasuringtheManifoldPressure......................... 22
AdjustingtheManifoldPressure........................... 22
RemovingtheManometer/PressureGauge...... 22
CompletingtheConversion.................................... 22
ELECTRICAL WIRING ...............................................23
LineVoltageWiring................................................ 23
Thermostat/LowVoltageConnections................. 23
HeatAnticipator.................................................... 24
Grounding............................................................... 24
START-UP&ADJUSTMENTS ...................................25
Pre-StartChecklist................................................. 25
Start-UpProcedures.............................................. 25
Verifying&AdjustingInputRate............................. 25
Verifying&AdjustingTemperatureRise................. 25
VerifyingBurnerOperation..................................... 26
VerifyingOperationoftheSupplyAir
LimitSwitch............................................................ 26
OPERATING SEQUENCE .........................................27
HeatingCycle......................................................... 27
CoolingCycle......................................................... 27
FanMode............................................................... 27
MAINTENANCE .........................................................27
AirFilters................................................................ 28
BlowerCompartment.............................................. 28
CleaningofBurners................................................ 28
VentSystem........................................................... 28
HeatExchanger&BurnerMaintenance................. 28
Lubrication.............................................................. 28
TROUBLESHOOTING ...............................................29
DESCRIPTION OF COMPONENTS ..........................29
FIGURES & TABLES .................................................30
FurnaceDimensions............................................... 30
Figure24-ACabinetModels(Short)................... 30
Figure25-BCabinetModels(Tall)...................... 31
Figure26-BCabinetModels(TopReturnAir).... 32
WiringDiagram....................................................... 33
Figure27-M7RLWiringDiagram........................ 33
GasInformation...................................................... 34
Table8-GasFlowRates..................................... 34
Table9-GasPipeCapacities.............................. 34
Table10-HighAltitudeDerationChartfor
PropaneGas....................................... 35
Table11-Natural
GasHeatingValues.................35
Table12-HighAltitudeDerationChartfor
Nat.Gas-HighHeatingValues........... 35
Table13-HighAltitudeDerationChartfor
Nat.Gas-LowHeatingValues............ 35
VentingInformation................................................ 36
Table14-VentTerminationClearances............... 36
Figure28-Horizontal&VerticalVenting.............. 37
INSTALLATION / PERFORMANCE CHECKLIST .....40
TABLE OF CONTENTS
3
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.
CAUTIONindicates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27(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.
4
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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pages18-19.
• Thisfurnaceisdesignedtooperatewithamaximum
externalpressureriseof0.3inchesofwatercolumn.
ConsultTable6(page26)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.
5
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
2
minimum.Forspecialclearancesbetween1”&
6”,requirementsarealouvereddoorwithaminimum
of250in
2
(1613cm
2
)freearea.For1”clearancefrom
furnace, use afully louvereddoor with atleast 400
in
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
VENT
6
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.
7
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.
8
MaximumDirectVent,DualPipeLength(FT.)
M7RL 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
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
28,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
alongtheventpipe,oneithersideoftheexteriorwall
(Figure28).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33)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36).
• 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
9
• 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
4 ft
12 in.
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)
10
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
pipesDO 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
11
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
B
Dual trunk duct
w/crossover connector
C
Transition duct
w/branches
Figure 6. Typical Supply Duct Systems
Return Air Connections
• M7furnaceswithmodelnumbersendinginAWorBW
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24&25(pages30&31).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26(page32).NOTE:Fortopreturninstallations,
12
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
(2,270cm
2
).Atleastone
registershouldbelocatedwhereitisnotlikelytobe
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
2
(1,516cm
2
).
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
2
(1,613cm
2
)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
(2,580cm
2
)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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.
• M7RLfurnaces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.
13
• 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
14
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24-26(pages
30-32)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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
15
14 1/2”
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.
C
L
20"
2 3/4
Figure 9. Floor Cutout Dimensions
CEILING CUT-OUTS FOR
VENT & COMBUSTION AIR
C
L
20"
23 3/4"
REAR WALL OF CLOSET OR ALCOVE
FURNACE
OUTER
DOOR
FURNACE OUTLINE
21 7/8
2 1/2
2 3/4
C
L
C
L
C
L
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 oor, must be
carefully located to avoid misalignment of the furnace.
Tolocatestandardducts,seeFigure9.Forroundducts,
seeFigure10.
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).SeeFigures9or10.
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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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.
16
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
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
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12(page16).
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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
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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).
4. Securetheductconnectortabstothesupplyairduct
with staples (3 minimum) or sheet metal screws (2
minimum).
Figure12.NarrowAirDucts-Option1
Cutting
Option A
Supply
Air Duct
Fold duct flap here
Remove
this Flap
Cut Here
Cut Here
Cut Here
Cut Here
Cut Here
Cut Here
Cut Here
Cut Here
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
17
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
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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.
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24-26(pages
30-32).
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15or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.
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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.
18
Figure 17. Condensate Drainage
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
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
19
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
(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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.
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
4
Gas Valve
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 18. 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.
20
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lowheatingvaluesat
sealevel.Tables12&13(page35)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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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
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19.
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.
meterandusingthelocalgasheatingvalue.SeeVerifying
&AdjustingtheInputRatesection(page25).
IMPORTANT NOTE: Observe the action of the burners
to make sure there is no yellowing, lifting or flashback
of the flame.
Inlet
Pressure
Tap
Manifold
Pressure Tap
On / Off Knob
Terminal
Connectors
N
A
T
N
A
T
L
P
L
P
OR
OTHER SIDE
OF CAP
Adjusting Screw
Regulator Cap
Figure 19. Gas Valve
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Unbranded M7RL Series Installation guide

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