SECTION
8
: V
ENTING
39
8
.11 Outside Combustion Air Supply
IMPORTANT: If the building has a slight negative
pressure or corrosive contaminants, such as
halogenated hydrocarbons, are present in the air, an
outside combustion air supply to the heater is
required. Seal all combustion air pipe joints.
Use of optional outside combustion air is not
recommended with unvented heaters.
The air supply duct may have to be insulated to
prevent condensation on the outer surface. The
outside air terminal must not be more than 1' (31 cm)
above the vent terminal.
8
.11.1 Len
g
th Re
q
uirements
Follow the constraints listed
on Page 35, Section 8.6
.
8
.11.2 Vertical Outside Air Supply for Sin
g
le Heater Installation
8
.11.3 Horizontal Outside Air Supply for Sin
g
le Heater Installation
Band Clamp
(Recommended)
Flex Hose
(Recommended)
Vent Cap
Roof
4" (10 cm)
Single Wall Pipe
Burner
18" (46 cm)
Min.
Description
Part Number
Vent Cap 4" (10 cm)
90502300
Band Clamp
(Recommended)
Flex Hose
(Recommended)
Vent Cap
W
all
4" (10 cm)
Single Wall Pipe
Burner
Description
Part Number
Vent Cap 4" (10 cm)
90502300
