Roberts Gorden Vantage twin Fire Unitary Infrared Heater TF-250 - Manual (Page 48)

TF-S ERIES I NSTALLATION , O PERATION AND S ERVICE M ANUAL
42
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 38, Section 9.6.
9.13.2 Vertical Outside Air Supply
Minimum of
2’ (0.61 m)
Description Part Number
Vent Cap 5" (13 cm) 90502301