12
INSTALLATION CONSIDERATIONS
•
Ensure upflow or horizontal furnaces are not installed
directly on carpeting, or any other combustible mate-
rial. The only combustible material allowed is wood.
•
Exposure to contaminated combustion air will result
in safety and performance-related problems. Do not
install the furnace where the combustion air is ex-
posed to the following substances:
chlorinated waxes or cleaners
chlorine-based swimming pool chemicals
water softening chemicals
deicing salts or chemicals
carbon tetrachloride
halogen type refrigerants
cleaning solutions (such as perchloroethylene)
printing inks
paint removers
varnishes
hydrochloric acid
cements and glues
antistatic fabric softeners for clothes dryers
and masonry acid washing materials
•
Isolate a
non-direct vent
furnace if it is installed near
an area frequently contaminated by any of the above
substances. This protects the
non-direct vent
furnace
from airborne contaminants. To ensure that the en-
closed
non-direct
vent
furnace has an adequate sup-
ply of combustion air, vent from a nearby uncontami-
nated room or from outdoors. Refer to the
Combus-
tion and Ventilation Air Requirements
section in this
manual or the installation instructions for details.
•
If the furnace is used in connection with a cooling
unit, install the furnace upstream or in parallel with
the cooling unit coil. Premature heat exchanger fail-
ure will result if the cooling unit coil is placed in the
return air of the furnace.
•
If the furnace is installed in a residential garage, posi-
tion the furnace so that the burners and ignition source
are located not less than 18 inches (457 mm) above
the floor. Protect the furnace from physical damage
by vehicles.
•
If the furnace is installed horizontally, the furnace ac-
cess doors must be vertical so that the burners fire
horizontally into the heat exchanger. Do not install
the unit with the access doors on the “up/top” or “down/
bottom” side of the furnace.
•
On counterflow installations, the air conditioning coil
must be downstream on the supply (positive) side of
the furnace heat exchanger.
•
Counterflow Installation over a noncombustible floor.
Before setting the furnace over the plenum opening,
ensure the surface around the opening is smooth and
level. A tight seal should be made between the fur-
nace base and floor by using a silicone rubber caulk-
ing compound or cement grout.
•
Counterflow Installation over a combustible floor.
If
installation over a combustible floor becomes neces-
sary, use an accessory sub-base (see Specification
Sheet applicable for your model for details). A spe-
cial accessory sub-base must be used for upright
counterflow unit installations over any combustible
material including wood. Refer to sub-base instruc-
tions for installation details. Follow the instructions
with the sub-base for proper installation. Do not in-
stall the furnace directly on carpeting, tile, or other
combustible material other than wood flooring.
(
NOTE:
The sub-base will not be required if an air con-
ditioning coil is installed between the supply air open-
ing on the furnace and the floor.)
C
LEARANCES
AND
A
CCESSIBILITY
Installations must adhere to the clearances to combustible
materials to which this furnace has been design certified.
The minimum clearance information for this furnace is pro-
vided on the unit’s clearance label. These clearances must
be permanently maintained. Refer to Specification Sheet for
minimum clearances to combustible materials. Clearances
must also accommodate an installation’s gas, electrical,
and drain trap and drain line connections. If the alternate
combustion air intake or vent/flue connections are used on
a 90% furnace, additional clearances must be provided to
accommodate these connections. Refer to
Vent Flue Pipe
and Combustion Air Pipe
section in this manual or the
installation instructions for details.
NOTE:
In addition to the
required clearances to combustible materials, a minimum
of 24 inches service clearance must be available in front of
the unit.
A furnace installed in a confined space (i.e., a closet or util-
ity room) must have two ventilation openings with a total
minimum free area of 0.25 square inches per 1,000 BTU/hr
of furnace input rating. One of the ventilation openings must
be within 12 inches of the top; the other opening must be
within 12 inches of the bottom of the confined space. In a
typical construction, the clearance between the door and
door frame is usually adequate to satisfy this ventilation re-
quirement.
Position
Sides
Rear
Front
Bottom
Flue
Top
Upflow
0"
0"
1"
C
0"
1"
Horizontal
6"
0"
1"
C
0"
4"
DM96VE Minimum Clearances To Combustible Materials
Position
Sides
Rear
Front
Bottom
Flue
Top
Counterflow
0"
0"
1"
NC
0"
Horizontal
6"
0"
1"
C
0"
6"
DC96VE Minimum Clearances To Combustible Materials
• C = If placed on combustible floor, floor must be wood only.
