INSTALLATION INSTRUCTIONS
Gas Furnace: N9MSE
440 01 4103 03
53
Specifications subject to change without notice.
Table 14
MAXIMUM EQUIVALENT VENT LENGTH
- Feet (Meters)
Note:
Maximum Equivalent Vent Length (MEVL) does NOT include elbows or terminations
Use
Table 15
−
DEDUCTIONS FROM MEVL to determine allowable vent length for each application.
Altitude
FT (M)
Unit Size
BTU/Hr
DIRECT VENT (2-PIPE) AND NON-DIRECT VENT (1-PIPE)
Vent Pipe Diameter (in.)
1-1/2
2
2-1/2
3
4
0 to 2000
(0 to 610)
40,000
3
50
(15.2)
210
(64.0)
250
(76.2)
NA
2
NA
60,000
30
(9.1)
135
(41.1)
235
(71.6)
265
(80.8)
NA
80,000
20
(6.1)
70
(21.3)
175
(53.3)
235
(71.6)
265
(80.8)
100,000
NA
25
(7.6)
110
(33.5)
235
(71.6)
265
(80.8)
120,000
NA
NA
15
(4.6)
100
(30.5)
250
(76.2)
140,000
4
NA
NA
10
(3.0)
90
(27.4)
210
(64.0)
2001 to 3000
(610 to 914)
40,000
45
(13.7)
198
(60.4)
232
(70.7)
NA
NA
60,000
27
(8.2)
127
(38.7)
222
(67.7)
250
(76.2)
NA
80,000
17
(5.2)
64
(19.5)
165
(50.3)
222
(67.7)
249
(75.9)
100,000
NA
22
(6.7)
104
(31.7)
223
(68.0)
250
(76.2)
120,000
NA
NA
11
(3.4)
93
(28.3)
237
(72.2)
140,000
4
NA
NA
NA
80
(24.4)
185
(56.4)
3001 to 4000
(914 to 1219)
40,000
39
(11.9)
184
(56.1)
214
(65.2)
NA
NA
60,000
23
(7.0)
119
(36.3)
210
(64.0)
235
(71.6)
NA
80,000
15
(4.6)
59
(18.0)
155
(47.2)
210
(64.0)
232
(70.7)
100,000
NA
19
(5.8)
98
(29.9)
211
(64.3)
236
(71.9)
120,000
NA
NA
8
(2.4)
86
(26.2)
224
(68.3)
140,000
4
NA
NA
NA
79
(24.1)
158
(48.2)
4001 to 4500
(1219 to 1370)
40,000
36
(11.0)
177
(53.9)
205
(62.5)
NA
NA
60,000
21
(6.4)
115
(35.1)
204
(62.2)
228
(69.5)
NA
80,000
14
(4.3)
56
(17.1)
150
(45.7)
202
(61.6)
224
(68.3)
100,000
NA
17
(5.2)
94
(28.7)
205
(62.5)
229
(69.8)
120,000
NA
NA
NA
83
(25.3)
217
(66.1)
140,000
4
NA
NA
NA
69
(21.0)
146
(44.5)
See notes at end of Venting Tables
See
Table 16
for altitudes over 4500 ft (1370m).
Figure 61
Elbows Configurations
LONG
MEDIUM
MITERED
L11F082
Figure 62
Vent Terminal Configurations
L11F083
CONCENTRIC
A13110
STANDARD 2
−
IN.,
3
−
IN. OR OPTIONAL
4
−
IN. TERMINATION
Table 15
DEDUCTIONS FROM MAXIMUM EQUIVALENT VENT LENGTH
- Feet (Meters)
Pipe Diameter (in):
11/2
2
21/2
3
4
Mitered 90º Elbow
8
(2.4)
8
(2.4)
8
(2.4)
8
(2.4)
8
(2.4)
Medium Radius 90º Elbow
5
(1.5)
5
(1.5)
5
(1.5)
5
(1.5)
5
(1.5)
Long Radius 90º Elbow
3
(0.9)
3
(0.9)
3
(0.9)
3
(0.9)
3
(0.9)
Mitered 45º Elbow
4
(1.2)
4
(1.2)
4
(1.2)
4
(1.2)
4
(1.2)
Medium Radius 45º Elbow
2.5
(0.8)
2.5
(0.8)
2.5
(0.8)
2.5
(0.8)
2.5
(0.8)
Long Radius 45º Elbow
1.5
(0.5)
1.5
(0.5)
1.5
(0.5)
1.5
(0.5)
1.5
(0.5)
Tee
16
(4.9)
16
(4.9)
16
(4.9)
16
(4.9)
16
(4.9)
Concentric Vent Termination
NA
0
(0.0)
NA
0
(0.0)
NA
Standard Vent Termination
0
(0.0)
0
(0.0)
0
(0.0)
0
(0.0)
0
(0.0)
Venting System Length Calculations
The Total Equivalent Vent Length for EACH combustion air or vent pipe equals the length of the venting system, plus the equivalent
length of elbows used in the venting system from
Table 15
.
Standard vent terminations or factory accessory concentric vent terminations count for zero deduction.
See vent system manufacturer’s data for equivalent lengths of flexible vent pipe or other termination systems. DO NOT ASSUME
that one foot of flexible vent pipe equals one foot of straight PVC/ABS DWV vent pipe.
Compare the Total Equivalent Vent Length to the Maximum Equivalent Vent Lengths in
Table 14
and
Table 16.
