16
0
1
2
3
4
5
6
7
45,000
2 or
2 1/2
201
196
191
186
181
176
171
166
70,000
2 or
2 1/2
140
135
130
125
120
115
110
105
90,000
2 or
2 1/2
20
15
10
90,000
3
122
115
108
101
94
87
80
73
115,000
2 or
2 1/2
15
10
5
115,000
3
112
105
98
91
84
77
70
63
Not Applicable
Not Applicable
Direct Vent (2 - Pipe) and Non-Direct Vent (1 - Pipe)
6
Maximum Allowable Length of Vent/Flue Pipe
& Combustion Air Pipe(ft)
(1) (2)
Unit Input
(Btu)
Pipe
Size
(4)
(in.)
Number of Elbows
(3) (5)
1) Maximum allowable limits listed on individual lengths for inlet and flue and
NOT a combination.
2) Minimum requirement for each vent pipe is five (5) feet in length and one
elbow/tee.
3) Tee used in the vent/flue termination must be included when determining
the number of elbows in the piping system.
4) 2 1/2” or 3” diameter pipe can be used in place of 2” diameter pipe.
5) Increased Clearance Configurations using (2) 45 deg. Long Sweep elbows
should be considered equivalent to one 90 deg. elbow.
6) One 90° elbow should be secured to the combustion air intake connection.
V
ENT
/F
LUE
P
IPE
T
ERMINATIONS
NOTE:
If either a 90 degree or 45 degree elbow is used for termina-
tion, it must be pointed downward.
The vent/flue pipe may terminate vertically, as through a roof, or hori-
zontally, as through an outside wall.
Vertical vent/flue pipe terminations should be as shown in the follow-
ing figure. Refer to
Section IX, Vent/Flue Pipe and Combustion Air
Pipe - Termination Locations
for details concerning location restric-
tions. The penetration of the vent through the roof must be sealed
tight with proper flashing such as is used with a plastic plumbing vent.
Horizontal vent/flue pipe terminations should be as shown in the fol-
lowing figure. Refer to
Section IX, Vent/Flue Pipe and Combustion Air
Pipe - Termination Locations
for details concerning location restric-
tions. 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 ce-
mented to a length of pipe connecting the two couplings. The length of
pipe 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 penetra-
tion should be sealed with silicone caulking material.
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.
NOTE: Terminate both pipes in the same pressure zone (same
side of roof, no major obstacles between pipes, etc.).
COMBUSTION AIR INTAKE
(OPTIONAL)
*Not required for
single pipe installation
TEE (OPTIONAL)
96
” M
AX
. -
3”
M
IN
.
RO
OF
LIN
E
INTAKE
SCREEN
OPTIONAL
12” MIN
HEIGHT DIFFERENCE
BETWEEN
INTAKE AND VENT
12” MIN TO ROOF OR HIGHEST
ANTICIPATED SNOW LEVEL
STRAIGHT
ELBOWS
_____________________________________
VENT/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
D
IRECT
V
ENT
(D
UAL
P
IPE
) P
IPING
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 resistant flashing. Both the com-
bustion air intake and a vent/flue pipe terminations must be in the same
atmospheric pressure zone. Refer to
Section IX, Vent/Flue and Com-
bustion Air Pipe - Termination Locations or Concentric Vent Termina-
tion
for specific details on termination construction. For details con-
cerning connection of pipes to the furnace, refer to the
Section IX,
Vent/Flue Pipe and Combustion Pipe - Standard Furnace Connec-
tions or Alternate Furnace Connections.
