c. If the furnace is installed on a raised platform to provide a
return-air plenum, and return air is taken directly from the
hallway or space adjacent to the furnace, all air for
combustion must come from outdoors. (See Fig. 3.)
2. All air from outside the structure:
a. If combustion air is taken from outdoors through vertical
ducts, the openings and ducts MUST have at least 1 sq in.
of free area per 4000 Btuh of the total input for all
equipment within the confined space.
b. If combustion air is taken from the outdoors through
horizontal ducts, the openings and ducts MUST have at
least 1 sq in. of free area per 2000 Btuh of the total input
for all equipment within the confined space.
c. When ducts are used, they must be of the same cross-
sectional area as the free area of the openings to which they
connect. The minimum dimension of rectangular ducts
must not be less than 3 in. (See Fig. 3.)
Step 3—Supply-Air Plenum Installation
(Downflow)
DOWNFLOW INSTALLATION
NOTE:
This furnace is approved for use on combustible flooring
when
manufacturer’s
accessory
floor
base
Part
No.
KGASB0201ALL is used. Manufacturer’s accessory floor base is
not required when this furnace is installed on manufacturer’s Coil
Assembly Part No. CD5 or CK5, or Coil Box Part No. KCAKC is
used.
1. Determine application being installed from Table 3.
2. Construct hole in floor per dimensions specified in Table 3
and Fig. 4.
3. Construct plenum to dimensions specified in Table 3.
4. If downflow subbase (KGASB) is used, install as shown in
Fig. 5.
If coil assembly CD5, CK5, or Coil Box KCAKC is used,
install as shown in Fig. 6.
INSTALLATION ON A COMBUSTIBLE FLOOR
1. Cut and frame hole in floor per dimensions in Installation
Instructions packaged with downflow subbase.
2. When completed, downflow subbase, plenum, and furnace (or
coil casing when used) should be installed as shown in Fig. 6.
Fig. 3—Air for Combustion and Ventilation
(Outside Air)
A93388
DUCTS TO
OUTDOORS
1 SQ IN.
PER 4000
BTUH
*
RETURN
AIR
VENT
THROUGH
ROOF
(CATEGORY I)
D
B
A
C
E
1 SQ IN.
PER 4000
BTUH
DUCT
TO
OUTDOORS
SUPPLY AIR
1 SQ IN.
PER 2000
BTUH*
DUCTS
TO
OUTSIDE
12
″
MAX
12
″
MAX
CONFINED
SPACE
12
″
MAX
12
″
MAX
1 SQ IN.
PER 4000
BTUH
*
OUTDOORS
1 SQ IN.
PER 4000
BTUH
*
1 SQ IN.
PER 2000
BTUH*
12
″
MAX
Use any of the following
combinations of openings:
A & B C & D D & E F & G
NOTE:
*Minimum dimensions of 3-In.
F
G
For Example:
58ZAV FURNACE
INPUT BTUH
FREE AREA PER
OPENING (SQ IN.)
ROUND PIPE
(IN. DIA)
46,000
11.5
4
69,000
17.3
5
92,000
23.0
6
115,000
28.8
7
135,000
34.5
7
For Example:
58ZAV FURNACE IN-
PUT BTUH
FREE AREA PER
OPENING (SQ IN.)
ROUND PIPE
(IN. DIA)
46,000
23.0
6
69,000
34.3
7
92,000
46.0
8
115,000
57.6
9
135,000
69.0
10
5
→
