Lennox G24M SERIES

Page 5
WARNING
Product contains fiberglass wool.
Disturbing the insulation in this product during
installation, maintenance, or repair will expose you
to fiberglass wool. Breathing this may cause lung
cancer. (Fiberglass wool is known to the State of
California to cause cancer.)
Fiberglass wool may also cause respiratory, skin,
and eye irritation.
To reduce exposure to this substance or for further
information, consult material safety data sheets
available from address shown below, or contact your
supervisor.
Lennox Industries Inc.
P.O. Box 799900
Dallas, TX 75379-9900 USA
Combustion, Dilution & Ventilation Air
In the past, there was no problem in bringing in sufficient
outdoor air for combustion. Infiltration provided all the air
that was needed. In today's homes, tight construction pracĆ
tices make it necessary to bring in air from outside for comĆ
bustion. Take into account that exhaust fans, appliance
vents, chimneys, and fireplaces force additional air that
could be used for combustion out of the house. Unless outĆ
side air is brought into the house for combustion, negative
pressure (outside pressure is greater than inside pressure)
will build to the point that a downdraft can occur in the furĆ
nace vent pipe or chimney. As a result, combustion gases
enter the living space creating a potentially dangerous situĆ
ation.
In the absence of local codes concerning air for combusĆ
tion and ventilation, use the guidelines and procedures in
this section to install G24M furnaces to ensure efficient and
safe operation. You must consider combustion air needs
and requirements for exhaust vents and gas piping. A porĆ
tion of this information has been reprinted with permission
from the National Fuel Gas Code (ANSIĆZ223.1). This reĆ
printed material is not the complete and official position of
the ANSI on the referenced subject, which is represented
only by the standard in its entirety.
In Canada, refer to the standard CAN/CGA B149.1 and
B149.2 installation codes.
CAUTION
Do not install furnace in a corrosive or contaminated
atmosphere. Meet all combustion and ventilation air
requirements, as well as all local codes.
CAUTION
Insufficient combustion air can cause headaches,
nausea, dizziness or asphyxiation. It will also cause
excess water in the heat exchanger resulting in rustĆ
ing and premature heat exchanger failure. Excessive
exposure to contaminated combustion air will result
in safety and performance related problems. Avoid
exposure to the following substances in the combusĆ
tion air supply:
Permanent wave solutions
Chlorinated waxes and cleaners
Chlorine base swimming pool chemicals
Water softening chemicals
DeĆicing salts or chemicals
Carbon tetrachloride
Halogen type refrigerants
Cleaning solvents (such as perchloroethylene
Printing inks, paint removers, varnishes, etc.
Hydrochloric acid
Cements and glues
Antistatic fabric softeners for clothes dryers
Masonry acid washing materials
All gasĆfired appliances require air for the combustion proĆ
cess. If sufficient combustion air is not available, the furĆ
nace or other appliance will operate inefficiently and unĆ
safely. Enough air must be provided to meet the needs of all
fuelĆburning appliances and appliances such as exhaust
fans which force air out of the house. When fireplaces, exĆ
haust fans, or clothes dryers are used at the same time as
the furnace, much more air is required to ensure proper
combustion and to prevent a downdraft. Insufficient air
causes incomplete combustion which can result in carbon
monoxide.
In addition to providing combustion air, fresh outdoor air diĆ
lutes contaminants in the indoor air. These contaminants
may include bleaches, adhesives, detergents, solvents
and other contaminants which can corrode furnace compoĆ
nents.
The requirements for providing air for combustion and venĆ
tilation depend largely on whether the furnace is installed in
an unconfined or a confined space.
Unconfined Space
An unconfined space is an area such as a basement or
large equipment room with a volume greater than 50 cubic
feet (1.42 m
3
) per 1,000 Btu (.29 kW) per hour of the comĆ
bined input rating of all appliances installed in that space.
This space also includes adjacent rooms which are not
separated by a door. Though an area may appear to be unĆ
confined, it might be necessary to bring in outdoor air for
combustion if the structure does not provide enough air by