9
WARNING:
Do not place combustible material on or against
the unit cabinet. Do not place combustible
materials, including gasoline and any other
flammable vapors and liquids, in the vicinity of
the unit.
AIR SUPPLY FOR COMBUSTION AND
VENTILATION
Provisions must be made in the installation of this unit
to provide an adequate supply of air for combustion.
Detailed instructions for determining the adequacy of
an installation can be found in the current revision of the
NationalFuelGasCode(ANSIZ223.1)andNFPA54,or
inCanadianinstallationcodes(CAN/CGA-B149),orin
applicable local building codes. Consult local codes for
special requirements.
WARNING:
Installation using methods other than those
described in the following sections must comply
withthe NationalFuelGasCodeandallapplicable
local codes to provide sufficient combustion air
for the furnace.
If the unit is operated with inadequate combustion air
supplytheameroll-outcontrollocatedabovetheburners
willopen,turningoffthegassupplytotheburners.The
ameroll-outcontrolisamanuallyre-setabledevice.DO
NOTinstallajumperwireacrossthiscontroltodefeat
itsfunction.DONOTresetthecontrolwithoutidentifying
and correcting the fault condition which caused the
controltotrip.Ifthiscontrolmustbereplaced,useonly
the replacement part specified in the Replacement Parts
List.
Air Openingsinthedooroftheunit,warmairregisters,
and return air grilles must not be restricted.
Tomaximizeheatexchangerlife,thecombustionair
must be free of chemical contaminants which form
corrosiveacidiccompounds whencombusted.Some
examplesofthesechemicalcontaminantsarechlorine,
fluorine,and sulphur.Somecommonsourcesof these
chemical contaminants are detergents, bleaches,
aerosol sprays, cleaning solvents, and a wide variety
of commercial and household products.
WARNING:
Combustible air must not be drawn from a
contaminatedatmosphere.Excessiveexposure
to contaminated combustion air will result in
safety and performance related problems.
CIRCULATING AIR SUPPLY
WARNING:
Products of combustion must not be allowed to
enterthereturnair ductworkorthe circulatingair
supply.Failuretopreventproductsof combustion
from being circulated into the living space can
createpotentiallyhazardousconditions including
carbonmonoxidepoisoningthatcouldresultin
personal injury or death.
All return ductwork must be adequately sealed,
all joints must be taped, and the ductwork must
be secured to the unit with sheet metal screws.
When return air is provided through the bottom
of the unit, the joint between the unit and the
return air plenum must be air tight.
The roof curb or cement pad on which the unit is
mountedmustprovidesoundphysicalsupportof
theunitwith no gaps,cracks,orsaggingbetween
the unit and the curb or pad.
Return air and circulating air ductwork must
not be connected to any other heat producing
device such as a fireplace insert, stove, etc.
Doingso mayresultin re,explosion, carbon
monoxidepoisoning,personalinjury,orproperty
damage.
Thisunitisdesignedonlyforusewithasupplyandreturn
duct.Airductsshouldbeinstalledinaccordancewithall
applicable local codes and the standards of the National
Fire Protection Association “Standard for Installation of
AirConditioningSystems”(NFPA90A),and“Standardfor
InstallationofResidenceTypeWarmAirHeatingandAir
ConditioningSystems”(NFPA90B).
Design the ductwork according to methods described
bytheAirConditioningContractorsofAmerica(ACCA)
ManualD.Theductsmustbeproperlysizednottoexceed
0.2inchesWCpressuredropat400scfmpernominal
ton of cooling capacity.
Ductworkshouldbeattacheddirectlytotheunitanges
forhorizontalapplications.Onroofcurbinstallationsthe
ductsmustbe attached to the curbductsupports,not
the unit.
Itisrecommendedthattheoutletductbeprovidedwith
a removable access panel. This opening should be
accessiblewhentheunitisinstalledinserviceandshall
beofasizesuchthatthesmokeorreectedlightmay
be observed inside the casing to indicate the presence
