Manual

17
V
ENT/FLUE TEE (OPTIONAL)
or
90° ELBOW TURNED
DOWN
12" MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
12" MIN.
Horizontal Termination (Single Pipe)
Above Highest Anticipated Snow Level
DIRECT VENT (DUAL PIPE) PIPING
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 Section IX, Vent/Flue and Combustion Air Pipe - Termina-
tion Locations or Concentric Vent Termination for specific details
on termination construction. For details concerning connection of
pipes to the furnace, refer to the Section IX, Vent/Flue Pipe and
Combustion Pipe - Standard Furnace Connections or Alternate
Furnace Connections.
VENT/FLUE AND COMBUSTION AIR PIPE LENGTHS AND 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.
Vertical pipe terminations should be as shown in the following
figure. Refer to Section IX, Vent/Flue Pipe and Combustion Pipe -
Termination Locations for details concerning location restrictions.
The penetrations through the roof must be sealed tight with proper
flashing such as is used with a plastic plumbing vent.
V
ENT/FLUE
COMBUSTION
AIR INTAKE
SCREEN
OPTIONAL
12" MIN. TO ROOF
OR HIGHEST ANTICIPATED
SNOW LEVEL
12" MIN.
TEE (OPTIONAL)
Vertical Terminations (Dual Pipe)
Horizontal terminations should be as shown in the following fig-
ure. Refer to Section IX, Vent/Flue Pipe and Combustion Pipe -
Termination Location for location restrictions. A 2 3/8” diameter
wall penetration is required for 2” diameter pipe. A 3” diameter hole
is required for a 2 1/2” pipe and a 3 1/2” diameter hole is required
for 3” diameter pipe. To secure the pipe passing through the wall
and prohibit damage to piping connections, a coupling should be
installed on either side of the wall and solvent cemented to a pipe
connecting the two couplings. The pipe length should be the wall
thickness plus the depth of the socket fittings to be installed on the
inside and outside of the wall. The wall penetration should be
sealed with silicone caulking material.
SCREEN
(OPTIONAL)
90º or 45°
MEDIUM RADIUS
ELBOWS
12" MIN
3" MIN
24" MAX
3" MIN
24" MAX
12" MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
12" MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
Standard Horizontal Terminations (Dual Pipe)