Service manual

TF-SERIES INSTALLATION, OPERATION AND SERVICE MANUAL
40
9.13 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.
For TF-120 4" (10 cm) single wall pipe or for
TF-160/200/250/300/350/380 5" (13 cm) single wall
pipe, PVC pipe, aluminum flex duct, or equivalent
may be used for outside air supply.
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.
9.13.1 Length Requirements
Follow the constraints listed on Page 36, Section 9.6.
9.13.2 Vertical Outside Air Supply
Burner
Tube
Secure with (3)
#8 x 3/8 Sheet
Metal Screws
Single Wall
Vent Pipe
Minimum of
18" (46 cm)
Suggestion: Wrap pipe
with insulation to prevent
condensation from forming
on outside of pipe.
Approved
Vent Cap
Description Part Number
Vent Cap 5" (13 cm) 90502301