J962V Installation Manual

9
Outdoor Air Using Horizontal Ducts
If combustion air is taken from outdoors through horizontal
ducts, the openings and ducts must have a minimum free
area of one square inch per 2,000 Btuh of total appliance
input. Ducts must have cross - sectional area at least as
large as the free area of their respective openings to the
furnace space. See Figure 5.
Air Directly Through an Exterior Wall
If combustion air is provided directly through an exterior
wall, the two openings must each have free area of at
least one square inch per 4,000 Btuh of total appliance
input. See Figure 6.
Figure 4. Combustion Air Drawn from Outside
Through Vertical Ducts
TOTAL INPUT
RATING (BTUH)
MINIMUM FREE AREA
(EACH OPENING)
ROUND DUCT
DIAMETER
38,000 10 sq. In 4 inches
60,000 15 sq. In 5 inches
80,000 20 sq. In 5 inches
100,000 25 sq. In 6 inches
120,000 30 sq. In 6 inches
140,000 35 sq. In 7 inches
160,000 40 sq. In 8 inches
Air Duct must be
at least 1 sq. in.
per 4,000 Btuh of
total input rating.
Ducts must
extend above
attic insulation.
Air Duct must be
at least 1 sq. in.
per 4,000 Btuh of
total input rating.
Ventilation Louvers
at each end of attic
Attic
Insulation
12" Max
Furnace
Water
Heater
Vent or
Chimney
Water
Heater
Vent or
Chimney
- - - - - - - - -
- - - - - - - - -
Furnace
Ventilation Louvers For
Unheated Crawl Space
- - - - - - - - -
Inlet Air
Ventilation Louvers
(each end of attic)
NOTE: Air openings shall
each have a free area of
not less than one square
inch per 4,000 Btuh of the
total input rating of all
equipment in the enclosure
.
- - - - - - - - -
Alter
nate
Air Inlet
Outlet
Air
Figure 3. Combustion Air Drawn from a Crawl
Space or Vented Attic
Figure 5. Combustion Air Drawn from Outside
Through Horizontal Ducts
TOTAL INPUT
RATING (BTUH)
MINIMUM FREE AREA
(EACH OPENING)
ROUND DUCT
DIAMETER
38,000 20 sq. In 5 inches
60,000 30 sq. In 6 inches
80,000 40 sq. In 7 inches
100,000 50 sq. In 8 inches
120,000 60 sq. In 9 inches
140,000 70 sq. In 10 inches
160,000 80 sq. In 10 inches
Furnace
Water
Heater
Air Ducts must be
at least 1 sq. in.
per 2,000 Btuh of
total input rating.
Vent or
Chimney
Air Duct
Air Duct
TOTAL INPUT
RATING (BTUH)
MINIMUM FREE AREA
(EACH OPENING)
ROUND DUCT
DIAMETER
38,000 10 sq. In 4 inches
60,000 15 sq. In 5 inches
80,000 20 sq. In 5 inches
100,000 25 sq. In 6 inches
120,000 30 sq. In 6 inches
140,000 35 sq. In 7 inches
160,000 40 sq. In 8 inches
NOTE:
Each opening to outside
must be at least 1 sq. in. per
4,000 Btuh of total input rating.
12" Max.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Furnace
Water
Heater
Vent or
Chimney
12"
Max
See
Note
See
Note
Figure 6. Combustion Air Drawn from Outside
Through an Exterior Wall