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V
ENT
/F
LUE
P
IPE
& C
OMBUSTION
A
IR
P
IPE
In a basement installation, the vent/flue pipe can be run between
joist spaces. If the vent pipe must go below a joist and then up into
the last joist space to penetrate the header, two 45° elbows should
be used to reach the header rather than two 90° elbows.
TEE (OPTIONAL)
12 " Min To Roof
Or Highest Anticipated
Snow Level
12 " Min To Roof
Or Highest Anticipated
Snow Level
Vertical Termination (Single Pipe)
12" MIN. TO ROOF
OR HIGHEST ANTICIPATED
SNOW LEVEL
90º
MEDIUM RADIUS
ELBOWS
Alternate Vertical Termination (Single Pipe)
MIN.
12"
FROM
WALL
12" TO GROUND OR
HIGHEST ANTICIPATED
SNOW LEVEL
Horizontal Termination (Single Pipe)
VENT/FLUE TEE
or
90° ELBOW TURNED
DOWN
12" MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
12" MIN.
Horizontal Termination (Single Pipe)
Above Highest Anticipated Snow Level
DIRECT V ENT (DUAL P IPE) PIPING
The inlet air screens provided in the installation instruction packet
are available for the installer to use in the inlet of the combustion air
pipe to prevent animals from building nests in the combustion air
pipe. Installation of screens, while strongly recommended, is not
required and will not affect performance of the unit.
Direct vent installations require both a combustion air intake and a
vent/flue pipe. The pipes may be run horizontally and exit through
the side of the building or run vertically and exit through the roof of
the building. The pipes may be run through an existing unused
chimney; however, they must extend a minimum of 12 inches
above the top of the chimney. The space between the pipes and
the chimney must be closed with a weather tight, corrosion resis-
tant flashing. Both the combustion air intake and a vent/flue pipe
terminations must be in the same atmospheric pressure zone.
Refer to Vent/Flue and Combustion Air Pipe - Termination Loca-
tions or Concentric Vent Termination for specific details on termi-
nation construction. For details concerning connection of pipes to
the furnace, refer to the Vent/Flue Pipe and Combustion Pipe -
Standard Furnace Connections or Alternate Furnace Connections.
VENT/FLUE &COMBUSTION A IR PIPE L ENGTHS &DIAMETERS
Refer to the following table for applicable length, elbows, and pipe
diameter for construction of the vent/flue and combustion air intake
pipe systems of a direct vent (dual pipe) installation. The number
of elbows tabulated represents the number of elbows and/or tees
in each (Vent/Flue & Combustion Air Intake) pipe. Elbows and/or
tees used in the terminations must be included when determining
the number of elbows in the piping systems.
If the combustion air intake pipe is to be installed above a finished
ceiling or other area where dripping of condensate will be objec-
tionable, insulation of the combustion air pipe may be required.
Use 1/2” thick closed cell foam insulation such as Armaflex™ or
Insultube™ where required.
VENT/FLUE AND COMBUSTION AIR PIPE TERMINATIONS
The vent/flue and combustion air pipes may terminate vertically, as
through a roof, or horizontally, as through an outside wall.