21
1
2
3
4
5
6
7
8
2 or 2 1/2
115
110
105
100
95
90
85
80
3
137
130
123
116
109
102
95
88
2 or 2 1/2
115
110
105
100
95
90
85
80
3
147
140
133
126
119
112
105
98
2 or 2 1/2
60
55
50
45
40
35
30
25
3
120
113
106
99
92
85
78
71
2 or 2 1/2
40
35
30
25
20
15
10
5
3
144
137
130
123
116
109
102
95
2 or 2 1/2
40
35
30
25
20
15
10
5
3
144
137
130
123
116
109
102
95
2 or 2 1/2
95
90
85
80
75
70
65
60
3
144
137
130
123
116
109
102
95
2 or 2 1/2
95
90
85
80
75
70
65
60
3
144
137
130
123
116
109
102
95
2 or 2 1/2
60
55
50
45
40
35
30
25
3
120
113
106
99
92
85
78
71
2 or 2 1/2
40
35
30
25
20
15
10
5
3
103
96
89
82
75
68
61
54
*MVM970803BNA*
*MVM970804CNA*
*MVM971005CNA*
*CVM971005CNA*
*MVM971205DNA*
*CVM970603BNA*
*CVM970803BNA*
*CVM970804CNA*
Direct Vent (2 - Pipe) and Non-Direct Vent (1- Pipe)
(6)
Pipe
Size
Model
Number of Elbows
*MVM970603BNA*
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 determin-
ing 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. elbows should be
considered equivalent to one 90 deg. elbow.
6) One 90° elbow should be secured to the combustion air intake connec-
tion.
7) For installations at or above 7,000 feet altitude, use 3” venting.
V
ENT
/F
LUE
P
IPE
T
ERMINATIONS
NOTE: If either a 90 degree or 45 degree elbow is used for
termination, it must be pointed downward.
The vent/flue pipe may terminate vertically, as through a
roof, or horizontally, as through an outside wall.
Vertical vent/flue pipe terminations should be as shown in
the following figure. Refer to
Vent/Flue Pipe and Combustion
Air Pipe - Termination Locations
for details concerning loca-
tion restrictions. 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 following figure. Refer to
Vent/Flue Pipe and Combustion
Air Pipe - Termination Locations
for details concerning loca-
tion restrictions. The wall penetration should be sealed
with silicone caulking material.
NOTE: Terminate both pipes in
the same pressure zone
(same side of roof, no major obstacles between pipes,
etc.).
COMBUSTION AIR INTAKE
(OPTIONAL)
*Not requ ired for
singl e pipe installation
TEE (OPTIONAL)
96
” M
AX
. -
3”
MI
N.
RO
OF
LIN
E
12” MIN
HEIGHT DIFFERENCE
BETWEEN
INTAKE AND VENT
12” MIN TO ROOF OR HIGHEST
ANTICIPATED SNOW LEVEL
Figure 13
STRAIGHT
ELBOWS
Figure 14
VENT/FLUE TEE (
or
45° ELBOW
TURNED DOWN or
90° ELBOW TURNED
DOWN
OPTIONAL)
12" MIN. ABOVE
HIGHEST ANTICIPATED
SNOW LEVEL
12" MIN.
Horizontal Termination (Single Pipe)
Above Highest Anticipated Snow Level
Figure 15
V
ENT
/F
LUE
& C
OMBUSTION
A
IR
P
IPE
L
ENGTHS
& D
IAMETERS
If there is a difference between the vent and combustion
air pipes, count the pipe with the most fittings. 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 objectionable, insulation of the combustion air pipe
may be required. Use 1/2” thick closed cell foam insulation
such as Armaflex™ or Insultube™ where required.
