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Horizontal
If you purchased a dual--position furnace, it can be installed hori-
zontally in an attic, basement, crawl space, alcove, or suspended
from a ceiling in a basement or utility room in either a right or left
airflow position. (see
Figure 3
)
The minimum clearances to combustibles
MUST
be maintained
between the furnace and adjacent construction, as shown in
Figure 1
.
ONLY
the corner of the cabinet is allowed to contact the
rafters
Figure 3
. All other clearances
MUST
be observed as
shown in
Figure 1.
Typical Horizontal Installation
Figure 3
VENT
GAS SUPPLY
SUPPLY
AIR
RETURN
AIR
25- 23- 18a
If the furnace is to be suspended from the floor joists in a crawl
space or the rafters in an attic, it is necessary to use steel pipe
straps or an angle iron frame to attach the furnace. These straps
should be attached to the furnace with sheet metal screws and to
the rafters or joists with bolts. The preferred method is to use an
angle iron frame bolted to the rafters or joists.
If the furnace is to be installed ground level in a crawl space, con-
sult local codes. A concrete pad 1
²
to 2
²
thick is recommended.
Thirty inches (30
²
) is recommended between the front of the fur-
nace and adjacent construction or other appliances. This should
be maintained for service clearance.
Keep all insulating materials clear from louvered door. Insulating
materials may be combustible.
The horizontal furnaces may be installed directly on combustible
wood flooring or supports, however, it is recommended for further
fire protection cement board or sheet metal is placed between the
furnace and the combustible wood floor and extend 12
²
beyond
the front of the furnace louver door. (This is a recommendation
only, not a requirement).
This furnace
MUST NOT
be installed directly on carpeting, tile or
other combustible material other than wood flooring or supports.
3. Combustion & Ventilation Air
CARBON MONOXIDE POISONING HAZARD.
Failure to provide adequate combustion and
ventilation air can result in death and/or personal
injury.
Use methods described here to provide combus-
tion and ventilation air.
!
Furnaces require ventilation openings to provide sufficient air for
proper combustion and ventilation of flue gases. All duct or open-
ings for supplying combustion and ventilation air must comply with
the gas codes, or in the absence of local codes, the applicable na-
tional codes.
When the installation is complete, check that all appliances have
adequate combustion air and are venting properly. See
Venting
And Combustion Air Check
in “
Gas Vent Installation”
Section in
this manual.
Contaminated Combustion Air
Installations in certain areas or types of structures will increase the
exposure to chemicals or halogens that may harm the furnace.
These instances must use only outside air for combustion.
The following areas or types of structures may contain or have ex-
posure to the substances listed below. The installation must be
evaluated carefully as it may be necessary to provide outside air
for combustion.
·
Commercial buildings.
·
Buildings with indoor pools.
·
Furnaces installed in laundry rooms.
·
Furnaces installed in hobby or craft rooms.
·
Furnaces installed near chemical storage areas.
·
Permanent wave solutions for hair.
·
Chlorinated waxes and cleaners.
·
Chlorine based swimming pool chemicals.
·
Water softening chemicals.
·
De--icing salts or chemicals.
·
Carbon tetrachloride.
·
Halogen type refrigerants.
·
Cleaning solvents (such as perchloroethylene).
·
Printing inks, paint removers, varnishes, etc.
·
Hydrochloric acid.
·
Sulfuric Acid.
·
Solvent cements and glues.
·
Antistatic fabric softeners for clothes dryers.
·
Masonry acid washing materials.
Confined Space Installation
NOTE
: A confined space is defined as an area with less than 50
cubic feet per 1,000 BTUH input rating for all gas appliances
installed in the area.
Air Openings and Connecting Ducts
1. Total input rating for all gas appliances
MUST
be considered
when determining free area of openings.
2. Connect ducts or openings directly to outside.
3. When screens are used to cover openings, the openings
MUST
be no smaller than
1
/
4
²
mesh.
4. The minimum dimension of rectangular air ducts
MUST NOT
be less than 3
²
.
