Filter
Top Products
Wheninstalled,thisfurnacemustbeelectricallygrounded
accordingtolocalcodes.Inaddition,intheUnitedStates,
installationmustconformwiththecurrentNationalElec-
tricCode,ANSI/NFPANo.70.TheNationalElectricCode
(ANSI/NFPANo.70)isavailablefromthefollowingad-
dress:
NationalFireProtectionAssociation
1BatteryMarchPark
Quincy,MA02269
InCanada,allelectricalwiringandgroundingfortheunit
mustbeinstalledaccordingtothecurrentregulationsofthe
CanadianElectricalCodePartI (CSAStandardC22.1)
and/orlocalcodes.
NOTE - This furnace is designed for a minimum continu-
ous return air temperature of 60°F (16°C) or an intermit-
tent operation down to 55°F (13°C) dry bulb for cases
where a night setback thermostat is used. Return air tem-
perature must not exceed 85°F (29 °C) dry bulb.
The G50UH(X) furnace may be installed in alcoves, clos-
ets, attics, basements, garages, and utility rooms in the up-
flow or horizontal position.
This furnace design has not been CSA International certi-
fied for installation in mobile homes, recreational vehicles,
or outdoors.
Lennox does not recommend the use of G50UH units as a
construction heater during any phase of construction. Very
low return air temperatures, harmful vapors and operation
of the unit with clogged or misplaced filters will damage the
unit.
G50UH units may be used for heating of buildings or struc-
tures under construction, if the following conditions are
met:
• The vent system must be permanently installed per
these installation instructions.
• A room thermostat must control the furnace. The use of
fixed jumpers that will provide continuous heating is not
allowed.
• The return air duct must be provided and sealed to the
furnace.
• Return air temperature range between 60°F (16°C) and
80°F (27°C) must be maintained.
• Air filters must be installed in the system and must be
maintained during construction.
• Air filters must be replaced upon construction comple-
tion.
• The input rate and temperature rise must be set per the
furnace rating plate.
• One hundred percent (100%) outdoor air must be pro-
vided for combustion air requirements during construc-
tion. Temporary ducting may supply outdoor air to the
furnace. Do not connect duct directly to the furnace.
Size the temporary duct following these instructions in
section for Combustion, Dilution and Ventilation Air in a
confined space with air from outside.
• The furnace heat exchanger, components, duct system,
air filters and evaporator coils must be thoroughly
cleaned following final construction clean-up.
• All furnace operating conditions (including ignition, in-
put rate, temperature rise and venting) must be verified
according to these installation instructions.
NOTE - The Commonwealth of Massachusetts stipu-
lates these additional requirements:
• Gas furnaces shall be installed by a ticensedptumb-
er or gas fitter only.
• The gas cock must be "T handle" type.
• When a furnace is installed in an attic, the passage-
way to and service area surrounding the equipment
shall be floored.
These instructions are intended as a general guide and do
not supersede local codes in any way. Consult authorities
having jurisdiction before installation.
In addition to the requirements outlined previously, the fol-
lowing general recommendations must be considered
when installing a G50UH(X) furnace:
• Place the furnace as close to the center of the air dis-
tribution system as possible. The furnace should also be
located close to the chimney or vent termination point.
• Do not install the furnace where drafts might blow direct-
ly into it. This could cause improper combustion and un-
safe operation.
• Do not block the furnace combustion air openings with
clothing, boxes, doors, etc. Air is needed for proper
combustion and safe unit operation.
• When the furnace is installed in an attic or other insu-
lated space, keep insulation away from the furnace.
WARNING
Page 5