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GENERAL INFORMATION
ABOUT THE FURNACE
• Thisfurnacehasbeentestedforcapacityandefciency
inaccordancewithAHRIStandardsand will provide
many years of safe and dependable comfort, providing
it is properly installed and maintained. With regular
maintenance, this unit will operate satisfactorily year
after year. Abuse, improper use, and/or improper
maintenance can shorten the life of the appliance and
create unsafe hazards.
• This furnace is designed to fulll the requirements
of being classified as a Category IV furnace. This
classification is related to the furnace’s Annual Fuel
UtilizationEfciency(AFUE)rating,thepercentageof
fuel that is converted into usable heating energy.
• Category IV furnaces typically have an AFUE rating
over 90% and are mainly vented through plastic PVC
pipe.
AIR FILTERS
WARNING:
Never operate the furnace without a lter in
place.Accumulatingdustinthereturnaircan
build up on internal components, resulting
inlossofefciency,equipmentdamage,and
possiblere.
• Anairlterissuppliedwiththefurnaceasshippedfrom
the factory.
• Thefurnaceshouldalways have acleanlter.Ifthe
filter becomes dirty, it should be cleaned or replaced.
The filter is installed over the return air grille of the door
inside the furnace cabinet.
• New or newly renovated homes may require more
frequent changing or cleaning until the construction
dust has minimized. Filters designed to remove
smaller particles such as pollen, may require additional
maintenance.
THERMOSTAT
• SingleStagegasfurnaces(M7RLseries)aredesignedto
be controlled by a conventional single stage thermostat.
Two-stagegasfurnaces(M7TLseries)willperformbest
withaconventionaltwo-stagethermostat.However,it
ispossibletocontroltheM7TLfurnacewithasingle
stage thermostat. Consult with your installer about which
type is best for your installation. Both thermostats are
commonly available at your local building supply store.
• Thethermostat’swiringmustcomplywiththecurrent
provisions of the NEC (ANSI/NFPA 70) and with
applicable local codes having jurisdiction. Thermostat
connections should be made according to the instructions
supplied with the thermostat and the indoor equipment.
• Thethermostatshouldbemountedabout5feetabove
the floor on an inside wall and not on an outside wall
or other location where its operation may be adversely
affected by radiant heat from fireplaces, sunlight, or
lighting fixtures, and convective heat from warm air
registers or electrical appliances.
• Thermostatstylesvary.Pleaserefertothethermostat
manufacturer’sUserManualfordetailedprogramming
instructions.
FURNACE IN A SMALL ROOM OR CLOSET
If a furnace is installed in relatively small utility room or
closet, the installation needs openings in the walls or door
toletreturnairin.Makesurethattheseopeningsremain
unobstructed. Do not modify these openings in any way
withoutconsultingalicensedHVACtechnician.
SOURCES OF CORROSION
It is known that certain common household chemicals can
cause heat exchanger corrosion if the vapors are pulled into
the furnace’s burners The following is a list of chemicals
that should not be used or stored near the furnace.
DO NOT STORE THESE CHEMICALS NEAR THE
FURNACE:
• Gasoline/Kerosene
• Permanentwavesolutions
• Chlorinatedwaxesandcleaners
• Chlorinebasedswimmingpoolchemicals
• Watersofteningchemicals
• De-icingsaltsorchemicals
• Carbontetrachloride
• Halogentyperefrigerants
• Cleaningsolvents(perchloroethylene)
• Printinginks,paintremovers,varnishes,etc.
• Hydrochloricacid
• Cementsandglues
• Antistaticfabricsofteners
• Masonryacidwashingmaterials
WARRANTY INFORMATION
A warranty certificate with full details is included with the
equipment. Carefully review these responsibilities with
your dealer or service company. The manufacturer will not
be responsible for any costs found necessary to correct
problems due to improper setup, improper installation,
adjustments, improper operating procedure on the part of
the user, Some specific examples of service calls which
are not included in the limited warranty are:
• Correcting wiring problems in the electrical circuit
supplying the equipment.
• Resettingcircuitbreakersorotherswitches.
• Adjustingorcalibratingofthermostat.