50
Table 17 – Maximum Equivalent Vent Length
NOTE: Maximum Equivalent Vent Length (MEVL) includes standard and concentric vent termination and does NOT include elbows.
Use Table 18
−
Deductions from Maximum Equivalent Vent Length to determine allowable vent length for each application.
Single Stage 92% - Ft.
Altitude
(feet)
Unit Size
40,000
1
60,000
2
80,000
100,000
3
120,000
3
Pipe Dia. (in) 1
½
2
2
½
1
½
2
2
½
3
1
½
2
2
½
3
4
2
2
½
3
4
2
½
3
4
0-2000
20
85
185
20
100
175
200
15
55
130
175
200
20
80
175
200
10
75
185
2001-3000
15
80
175
95
165
185
10
49
125
165
185
15
75
165
185
70
175
3001-4000
70
160
16
90
155
175
115
155
175
155
175
5
65
165
4001-4500
10
155
15
85
150
170
44
110
150
165
10
70
170
N/A
60
160
4501-5000
145
80
165
145
160
65
150
165
5001-6000
60
130
75
140
155
41
100
135
150
140
155
155
6001-7000
5
55
120
13
70
130
145
N/A
38
90
125
140
60
135
145
50
140
7001-8000
50
110
10
65
120
135
36
120
125
N/A
55
125
135
46
130
8001-9000
N/A
30
95
5
60
115
125
33
80
110
115
50
115
125
43
120
9001-10000
25
85
N/A
55
105
115
30
75
100
105
45
100
115
39
115
Single Stage 92% - Metric
Altitude
(meters)
Unit Size
40,000
1
60,000
2
80,000
100,000
3
120,000
3
Pipe Dia.
(mm)
38
51
64
38
5
64
76
38
51
64
76
102
51
64
76
102
64
76
102
0-610
6.0
25.9 56.3
6.0
30.4 53.3 60.9
4.5
16.7 39.6 53.3 60.9
6.0
24.3 53.3 60.9
3.0
22.8 56.3
611-914
4.5
24.3 53.3
28.9 50.2 56.3
3.0
14.9
38.1 50.2 56.3
4.5
22.8 50.2 56.3
21.3 53.3
915-1219
21.3
48.7
4.8
27.4 47.2 53.3
35.0 47.2 53.3
0.0
47.2
53.3
1.5
19.8 50.2
1220-1370
3.0
47.2
4.5
25.9
45.7
51.8
13.4
33.5 45.7 50.2
3.0
21.3
51.8
N/A
18.2
48.7
1371-1524
44.1
24.3
50.2
0.0
44.1 48.7
19.8 45.7 50.2
1525-1829
18.2 39.6
22.8 42.6 47.2
12.4 30.4 41.1 45.7
0.0
42.6 47.2
47.2
1830-2134
1.5
16.7 36.5
3.9
21.3 39.6 44.1
N/A
11.5 27.4
.1
42.6
18.2 41.1 44.1
15.2 42.6
2135-2438
15.2 33.5
3.0
19.8 36.5 41.1
10.9
0.0
36.5 38.1
N/A
16.7 38.1 41.1
14.0 39.6
2439-2743
N/A
9.1
28.9
1.5
18.2 35.0 38.1
10.0 24.3 33.5 35.0
15.2 35.0 38.1
13.1 36.5
2744-3048
7.6
25.9 N/A
16.7 32.0 35.0
9.1
22.8 30.4 32.0
13.7 30.4 35.0
11.8 35.0
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.) 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.
3. Inducer Outlet Restrictor disk (P/N 337683-402; 1.50-in. (38 mm) Dia.) 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.
Long
Medium
Mitered
Concentric
Standard 2-in., 3-in., or
optional 4-in. termination.
ELBOW CONFIGURATIONS
VENT TERMINAL CONFIGURATIONS
A13110
Table 18 – Deductions from Maximum Equivalent Vent Length
−
Ft. (M)
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)
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.
912S
