# 45465K005
Page 6
Figure 7
Inlet Air Restrictor Plate
The inlet air restrictor plate
must
be installed in all
installations using inside air for combustion (non-direct vent).
Contaminated Combustion Air
Excessive exposure to contaminated combustion air will
result in safety and performance related problems. The
recommended source of combustion air is outdoor air.
However, the use of indoor air in most applications is
acceptable if the following guidelines are followed:
1.
If the furnace is installed in a confined space, it is
recommended that the necessary combustion air
come from the outdoors by way of an attic, crawl
space, air duct, or direct opening.
2.
If indoor combustion air is used, there must be no
exposure to the substances listed in item 5.
3.
All provisions for indoor combustion air must meet the
requirements for combustion air indicated in the
National Fuel Gas Code, ANSI Z223.1/NFPA 54
(latest edition), and/or any applicable local codes. In
Canada, see CSA B149.1, Natural Gas and Propane
Installation Codes (latest edition).
4.
The following types of installation may require
out-
door air
for combustion, due to chemical exposures:
•
Commercial buildings
•
Buildings with indoor pools
•
Furnaces installed in laundry rooms
•
Furnaces installed in hobby or craft rooms
•
Furnaces installed near chemical storage areas
5.
Exposure to the following substances in the combustion
air supply may also require
outdoor air
for combustion:
•
Permanent wave solutions
•
Chlorinated waxes and cleaners
•
Chlorine-based swimming pool chemicals
•
Water softening chemicals
•
Deicing salts or chemicals
•
Carbon tetrachloride
•
Halogen-type refrigerants
•
Cleaning solvents (such as perchloroethylene)
•
Printing inks, paint removers, varnishes, etc.
•
Cements and glues
•
Antistatic fabric softeners for clothes dryers
•
Masonry acid washing materials
•
Chlorinated laundry products
•
Hydrochloric acid
Venting
This furnace has a fan-assisted combustion system designed
for vertical venting into a suitable chimney or listed gas vent,
and is classified as a Category I furnace (negative vent) as
shipped from the factory. This furnace is dual certified as a
direct vent using outside air for combustion or it can use air
from inside the structure. See Figures 14 – 16 on pages 11
and 12 for optional outside combustion air applications.
The furnace is shipped with the air inlet pipe terminated to
the top panel for either inside or outside combustion air. An
inlet air restrictor plate (see Figure 7) is supplied with this
furnace and can be found in the plastic bag containing these
Installation Instructions and the User’s Information Manual.
For installations using inside air for combustion, the inlet air
restrictor plate must be installed as shown in Figure 8. Two
different sized inlet restrictor plates are supplied with the
furnace (2" and 3"). The 3" restrictor plate should be used
with non-direct vented 100K and larger models only; all
other non-direct vented models use the 2" restrictor plate.
Figure 6
Equipment in Confined Space
All Air from Outside
(All Air Through Horizontal Ducts)
Chimney or
Gas Vent
Furnace
Water Heater
Outlet Air
Inlet Air
Note: Each air duct opening shall have a free area of at least one
square inch per 2000 BTU per hour of the total input rating of
all equipment in the enclosure. If the equipment room is
located against an outside wall and the air openings
communicate directly with the outdoors, each opening shall
have a free area of at least one square inch per 4000 BTU
per hour of the total input rating of all other equipment in the
enclosure.
