free area of at least 1-in.
2
/4,000 Btuh of total input rating for
all gas appliances in the space.
3. In spaces that use the Indoor Combustion Air Method,
infiltration should be adequate to provide air for combustion,
permanent ventilation and dilution of flue gases. However, in
buildings with unusually tight construction, additional air
MUST be provided using the methods described in the
Outdoor Combustion Air Method section.
Unusually tight construction is defined as
Construction with:
a. Walls and ceilings exposed to the outdoors have a continu-
ous, sealed vapor barrier. Openings are gasketed or sealed
and
b. Doors and openable windows are weatherstripped and
c. Other openings are caulked or sealed. These include joints
around window and door frames, between sole plates and
floors, between wall-ceiling joints, between wall panels, at
penetrations for plumbing, electrical and gas lines, etc.
Combination of Indoor and Outdoor Air
1. Indoor openings shall comply with the Indoor Combustion
Air Method below and,
2. Outdoor openings shall be located as required in the Outdoor
Combustion Air Method mentioned previously and,
3. Outdoor openings shall be sized as follows:
a. Calculate the Ratio of all Indoor Space volume divided by
required volume for Indoor Combustion Air Method
below.
b. Outdoor opening size reduction Factor is 1 minus the
Ratio in a. above.
c. Minimum size of Outdoor openings shall be the size
required in Outdoor Combustion Air Method above
multiplied by reduction Factor in b. above. The minimum
dimension of air openings shall be not less than 3 in. (80
mm).
INSTALLATION
UPFLOW INSTALLATION
Bottom Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return-air opening. Remove and discard this panel when
bottom return air is used. To remove bottom closure panel,
perform the following:
1. Tilt or raise furnace and remove 2 screws holding bottom filler
panel. (See Fig. 9.)
2. Rotate bottom filler panel downward to release holding tabs.
3. Remove bottom closure panel.
4. Reinstall bottom filler panel and screws.
Side Return Air Inlet
These furnaces are shipped with bottom closure panel installed in
bottom return-air opening. This panel MUST be in place when
only side return air is used.
NOTE:
Side return-air openings can be used in UPFLOW and
most HORIZONTAL configurations. Do not use side return-air
openings in DOWNFLOW configuration.
Leveling Legs (If Desired)
In upflow position with side return inlet(s), leveling legs may be
used. (See Fig. 10.) Install field-supplied, 5/16 X 1-1/2 in. (max)
corrosion-resistant machine bolts, washers and nuts.
NOTE:
Bottom closure must be used when leveling legs are used.
It may be necessary to remove and reinstall bottom closure panel
to install leveling legs. To remove bottom closure panel, see Item
1. in Bottom Return Air Inlet section.
To install leveling legs:
1. Position furnace on its back. Locate and drill a hole in each
bottom corner of furnace. (See Fig. 10.)
2. For each leg, install nut on bolt and then install bolt and nut in
hole. (Install flat washer if desired.)
3. Install another nut on other side of furnace base. (Install flat
washer if desired.)
4. Adjust outside nut to provide desired height, and tighten inside
nut to secure arrangement.
5. Reinstall bottom closure panel if removed.
DOWNFLOW INSTALLATION
NOTE:
For downflow applications, this furnace is approved for
use on combustible flooring when any one of the following 3
accessories are used:
•
Special Base, KGASB
•
Cased Coil Assembly Part No. CD5 or CK5
•
Coil Box Part No. KCAKC
1. Determine application being installed from Table 3.
2. Construct hole in floor per Table 3 and Fig. 11.
3. Construct plenum to dimensions specified in Table 3 and Fig.
11.
Fig. 9—Removing Bottom Closure Panel
A02098
Fig. 10—Leveling Legs
A89014
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