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NOTE: Maximum Equivalent Vent Length (MEVL) includes standard and concentric vent termination and does NOT include elbows.
Use Table 17 - Deductions from Maximum Equivalent Vent Length to determine allowable vent length for each application.
2
Unit Size
26,000
Pipe Dia.
1 ½
2
1 ½
(in)
0--- 2000
70
200
40
2001--- 3000
65
190
35
3001--- 4000
60
175
30
4001--- 4500
55
160
25
Altitude
4501--- 5000
(feet)
5001--- 6000
50
145
20
6001--- 7000
45
135
15
7001--- 8000
40
120
10
8001--- 9000
35
110
9001--- 1000
30
95
5
0
2
Unit Size
26,000
Pipe Dia.
38
51
38
(mm)
0--- 610
21.3
60.9
12.1
611--- 914
19.8
57.9
10.6
915--- 1219
18.2
53.3
9.1
1220--- 1370
Altitude
16.7
48.7
7.6
1371--- 1524
(meters)
1525--- 1829
15.2
44.1
6.0
1830--- 2134
13.7
41.1
4.5
2135--- 2438
12.1
36.5
3.0
2439--- 2743
10.6
33.5
2744--- 3048
9.1
28.9
1.5
NOTES:
1. Inducer Outlet Restrictor disk (P/N 337683 ---401; 1.25 ---in. (32 mm) Dia.) shipped in the loose parts bag or available through Replacement Components
required under 10 ---ft. (3 M) TEVL in all orientations. Required for installations from 0 --- 2000 (0 to 610 M) above sea level. Failure to use an outlet restric-
tor may result in flame disturbances or flame sense lock ---out.
2. Inducer Outlet Restrictor disk (P/N 337683 ---401; 1.25 ---in. (32 mm) Dia.) shipped in the loose parts bag or available through Replacement Components
required for no greater than 5 ---ft. (1.5 M) TEVL in downflow and horizontal orientations only. Required for installations from 0 --- 2000 (0 to 610 M) above
sea level.
ELBOW CONFIGURATIONS
Long
Medium
Pipe Diameter (in):
Mitered 90º Elbow
Medium Radius 90º Elbow
Long Radius 90º Elbow
Mitered 45º Elbow
Medium Radius 45º Elbow
Long Radius 45º Elbow
Tee
NOTES:
1. Use only the smallest diameter pipe possible for venting. Over ---sizing may cause flame disturbance or excessive vent terminal icing or freeze ---up.
2. NA --- Not allowed. Pressure switch will not close, or flame disturbance may result.
3. Vent sizing for Canadian installations over 4500 ft. (1370 M) above sea level are subject to acceptance by the local authorities having jurisdiction.
4. Size both the combustion air and vent pipe independently, then use the larger size for both pipes.
5. Assume the two 45_ elbows equal one 90_ elbow. Wide radius elbows are desirable and may be required in some cases.
6. Elbow and pipe sections within the furnace casing and at the vent termination should not be included in vent length or elbow count.
7. The minimum pipe length is 5 ft. (2 M) linear feet (meters) for all applications.
8. Use 3 ---in. (76 mm) diameter vent termination kit for installations requiring 4 ---in. (102 mm) diameter pipe.
Table 16 – Maximum Equivalent Vent Length - - Ft.
1
2
40,000
60,000
2
2 ½
1 ½
2
2 ½
3
155
185
100
175
200
20
150
175
95
165
185
135
160
16
90
155
175
130
155
85
150
170
125
145
15
80
145
165
120
130
75
140
155
110
120
13
70
130
145
100
110
10
65
120
135
90
95
5
60
115
125
80
85
N/A
55
105
115
Maximum Equivalent Vent Length --- Meters
1
2
40,000
60,000
51
64
38
51
64
76
47.2
56.3
30.4
53.3
60.9
6.0
45.7
53.3
28.9
50.2
56.3
41.1
48.7
4.8
27.4
47.2
53.3
39.6
47.2
25.9
45.7
51.8
38.1
44.1
4.5
24.3
44.1
50.2
36.5
39.6
22.8
42.6
47.2
33.5
36.5
3.9
21.3
39.6
44.1
30.4
33.5
3.0
19.8
36.5
41.1
27.4
28.9
1.5
18.2
35.0
38.1
24.3
25.9
NA
16.7
32.0
35.0
Mitered
Table 17 – Deductions from Maximum Equivalent Vent Length - - Ft. (M)
1-1/2
8
(2.4)
8
5
(1.5)
5
3
(0.9)
3
4
(1.2)
4
2.5
(0.8)
2.5
1.5
(0.5)
1.5
16
(4.9)
16
80,000
1 ½
2
2 ½
3
4
2
15
55
130
175
200
20
125
165
185
49
15
115
155
175
10
150
165
44
110
145
160
10
41
100
135
150
38
125
140
90
36
120
125
N/A
33
80
110
115
N/A
30
75
100
105
80,000
38
51
64
76
102
51
4.5
16.7
39.6
53.3
60.9
6.0
24.3
38.1
50.2
56.3
14.9
4.5
22.8
35.0
47.2
53.3
3.0
45.7
50.2
21.3
13.4
33.5
44.1
48.7
3.0
19.8
12.4
30.4
41.1
45.7
11.5
38.1
42.6
18.2
27.4
10.9
36.5
38.1
16.7
NA
10.0
24.3
33.5
35.0
NA
15.2
9.1
22.8
30.4
32.0
13.7
VENT TERMINAL CONFIGURATIONS
Concentric
2
2-1/2
(2.4)
8
(2.4)
(1.5)
5
(1.5)
(0.9)
3
(0.9)
(1.2)
4
(1.2)
(0.8)
2.5
(0.8)
(0.5)
1.5
(0.5)
(4.9)
16
(4.9)
47
100,000
120,000
2 ½
3
4
2 ½
3
4
2 ½
80
175
200
75
185
10
165
185
70
175
75
175
5
65
165
155
70
170
160
150
165
60
65
140
155
155
N/A
60
135
145
50
140
N/A
55
125
135
46
130
50
115
125
43
120
45
100
115
39
115
100,000
120,000
64
76
102
64
76
102
53.3
60.9
22.8
56.3
3.0
50.2
56.3
21.3
53.3
53.3
1.5
19.8
50.2
47.2
51.8
48.7
45.7
50.2
18.2
42.6
47.2
47.2
41.1
44.1
NA
15.2
42.6
38.1
41.1
14.0
39.6
35.0
38.1
13.1
36.5
30.4
35.0
11.8
35.0
Standard 2-in., 3-in., or
optional 4-in. termination.
3
8
(2.4)
8
5
(1.5)
5
3
(0.9)
3
4
(1.2)
4
2.5
(0.8)
2.5
1.5
(0.5)
1.5
16
(4.9)
16
140,000
3
4
5
65
155
140
60
120
50
110
45
100
35
80
30
65
25
45
15
30
10
15
140,000
64
76
102
1.5
19.8
47.2
42.6
18.2
36.5
15.2
33.5
13.7
30.4
NA
10.6
24.3
9.1
19.8
7.6
13.7
4.5
9.1
3.0
4.5
A13110
4
(2.4)
(1.5)
(0.9)
(1.2)
(0.8)
(0.5)
(4.9)
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