Nordyne G6RC 90+ Installation Instructions Manual page 12

Vent or
Chimney
Furnace
Water Heater
Minimum
Total Input Free Area
Rating (Btuh) (Each Opening)
40,000 100 sq. in.
60,000 100 sq. in.
80,000 100 sq. in.
Figure 9. Equipment in a Confined Space
with all Combustion Air drawn from Inside
Ventilation Louvers at each end of attic
Vent or
Chimney
Attic
Insulation
Furnace
Water Heater
Minimum
Total Input Free Area
(Each Opening)
Rating (Btuh)
40,000 10 sq. in.
15 sq. in.
60,000
80,000 20 sq. in.
25 sq. in.
100,000
120,000 30 sq. in.
35 sq. in.
140,000
160,000 40 sq. in.
Figure 11. Equipment in a Confined Space
with all Combustion Air drawn from
Outdoors through Vertical Ducts – from
Ventilated Attic
12
Each opening must
be at least 100 sq. in.
or 1 sq. in. per 1000
Btuh of total input
rating, whichever is
greater. See minimum
area per table.
12" Max.
12" Max.
Round Duct
Diameter
12"
12"
12"
Figure 10. Equipment in a Confined Space
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.
12" Max
Alternate
Round Duct
Diameter
4"
5"
5"
6"
6"
7"
8"
Figure 12. Equipment in a Confined Space
Vent or
Chimney
- - -
- - -
12"
- - -
Max
- - -
- - -
- - -
Water Heater
Minimum
Total Input Free Area
Rating (Btuh) (Each Opening)
40,000 10 sq. in.
60,000 15 sq. in.
80,000 20 sq. in.
100,000 25 sq. in.
120,000 30 sq. in.
140,000 35 sq. in.
160,000 40 sq. in.
with all Combustion Air drawn from
Outdoors through Exterior Wall
Vent or
Chimney
Water
Furnace
Heater
Inlet Air
Air Inlet
Ventilation Louvers For
Unheated Crawl Space
with all Combustion Air drawn from
Outdoors through Ventilated Crawl Space
and Ventilated Attic
Furnace
Round Duct
Diameter
4"
5"
5"
6"
6"
7"
8"
Ventilation Louvers
(each end of attic)
Outlet
NOTE: Air open-
Air ings shall each
have a free area
of not less than
one square inch
per 4,000 Btuh of
the total input rat-
ing of all equipment
in the enclosure.