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CAUTION
Before attempting to perform any service or maintenance,
turn the electrical power to unit OFF at the disconnect
switch.
NOTICE
Any additions, changes, or conversions required in order
for the appliance to satisfactorily meet the application
needs must be made by a licensed professional installer
(or equivalent) using factory-specified and approved
parts.
Safety Instructions
1 - Keep the furnace area clear and free of combustible
material, gasoline, and other flammable vapors
and liquids. If it is installed in an insulated area, the
furnace must be kept free of insulating material.
Insulating material may be combustible.
2 -
DO NOT
obstruct air flow to unit. Unit must receive
an unobstructed flow of combustion and ventilating
air. DO NOT block or obstruct air openings on
the furnace or air openings to the area in which
the furnace is installed. Take care to maintain
established clearances surrounding the furnace.
3 -
DO NOT
store chlorine or fluorine products near
unit or introduce these products into the combustion
air. These products can cause furnace corrosion.
4 -
DO NOT draw return air from a room where this
furnace, or any other gas appliance (ie., a water
heater), is installed.
When return air is drawn from
a room, a negative pressure is created in the room. If
a gas appliance is operating in a room with negative
pressure, the flue products can be pulled back down
the vent pipe and into the room. This reverse flow
of the flue gas may result in incomplete combustion
and the formation of carbon monoxide gas. This
toxic gas might then be distributed throughout the
house by the furnace duct system.
WARNING
The blower door must be securely in place when the
blower and burners are operating. Gas fumes, which
could contain carbon monoxide, can be drawn into the
living space resulting in personal injury or death.
Your furnace is a gas appliance.
It is critical that the gas
supplied to the unit be completely burned to avoid the pro-
duction of carbon monoxide gas. Complete combustion of
the gas requires, but is not limited to, correct gas pressure
and gas flow rate, adequate combustion air and proper
venting.
WARNING
Asphyxiation Hazard
The exhaust vent for this furnace must be leak-free and
must be securely connected to the furnace flue collar at
all times.
For your safety and to fulfill the terms of the limited
warranty, a licensed professional service technician (or
equivalent) must annually inspect this furnace and its
vent system.
Exposure to carbon monoxide gas can cause personal
injury and even death to all occupants, including pets.
Any item that is powered by, or gives off heat from, a
combustion process (including lawn mowers, automo-
biles, and fireplaces) has the potential to produce carbon
monoxide gas. Because of this,
Lennox recommends
the use of a carbon monoxide detector in your home,
even if you do not own gas appliances.
Reliable de-
tectors are available at reasonable retail prices. Contact
your Lennox dealer for more details about this invest-
ment in your safety.
Your furnace is designed to meet standards set by nation-
al agencies, and to operate safely when properly installed
and maintained. However, the unit’s performance can be
greatly impacted by the individual installation and the op-
erating environment. It is your responsibility to ensure that
this appliance is maintained.
Proper maintenance is critical for your safety and the sat-
isfactory operation m./of the product. Lennox strongly
recommends annual inspection and maintenance of this
appliance. Contact your Lennox dealer for an inspection
by a licensed professional service technician.
Start-Up & Operation
NOTE -
When the furnace begins heating mode, the di-
agnostic LED on the furnace control will display “H1” for
heating operation in 1st stage, or “H2” for heating opera-
tion in 2nd stage. The LED can be seen through the view-
port on the lower access panel. See figure 2.
WARNING
If you do not follow these instructions exactly, a fire or
explosion may result causing property damage, personal
injury or death.
BEFORE LIGHTING
smell all around the appliance area
for gas. Be sure to smell next to the floor because some
gas is heavier than air and will settle on the floor.
The gas valve on the SL280UHV is equipped with a gas
control switch. Use only your hand to move the gas con-
trol switch. Never use tools. If the switch will not move by
hand, do not try to repair it. Call a licensed professional
service technician (or equivalent). Force or attempted re-
pair may result in a fire or explosion.
