41
Table13—MaximumAllowablePipeLength ---Ft(M)(Continued)
ALTITUDE ---
FT (M)
UNIT SIZE
(BTUH)
DIRECT VENT (2-PIPE) ONLY
NON-DIRECT
VENT (1-PIPE)
ONLY
NUMBER OF 90° ELBOWS
TERMINATION
TYPE
PIPE DIA
(IN.)*
PIPE DIA (IN.)* 1 2 3 4 5 6
7001 to 8000‡
(2134 to 2438)
60,000
2Pipeor2-in
Concentric
1-1/2 (38) 1-1/2 (38)
12
(3.7)
7
(2.1)
NA NA NA NA
2 (51) 2 (51)
53
(16.2)
48
(14.6)
46
(14.)
41
(12.5)
40
(12.2)
38
(11.6)
80,000
2Pipeor2-in
Concentric
2 (51) 2 (51)
36
(11.0)
31
(9.4)
19
(5.8)
14
(4.3)
12
(3.7)
NA
2-1/2 (64) 2-1/2 (64)
66
(20.1)
65
(19.8)
63
(19.2)
62
(18.9)
60
(18.3)
59
(18.0)
100,000
2Pipeor3-in
Concentric
2-1/2 (64) 2-1/2 (64)
25
(7.6)
17
(5.2)
8
(2.4)
7
(2.1)
NA NA
3 (76) 3 (76)
63
(19.2)
58
(17.7)
53
(16.2)
48
(14.6)
43
(13.1)
38
(11.6)
120,000
2Pipeor3-in.
Concentric
3 (76)† no disk NA
20
(6.1)
13
(4.0)
7
(2.1)
NA NA NA
NA 3 (76)†#
46
(14.)
44
(13.4)
43
(13.1)
41
(12.5)
40
(12.2)
38
(11.6)
4 (102)† no
disk
4 (102)† no disk
61
(18.6)
56
(17.1)
51
(15.5)
46
(14.0)
41
(12.5)
36
(11.0)
ALTITUDE ---
FT (M)
UNIT SIZE
(BTUH)
DIRECT VENT (2-PIPE) ONLY
NON-DIRECT
VENT (1-PIPE)
ONLY
NUMBER OF 90° ELBOWS
TERMINATION
TYPE
PIPE DIA
(IN.)*
PIPE DIA (IN.)* 1 2 3 4 5 6
8001 to 9000‡
(2438 to 2743)
60,000
2Pipeor2-in
Concentric
1-1/2 (38) 1-1/2 (38)
11
(3.4)
6
(1.8)
NA NA NA NA
2 (51) 2 (51)
49
(14.9)
44
(13.4)
42
(12.8)
37
(11.3)
35
(10.7)
34
(10.4)
80,000
2Pipeor2-in
Concentric
2 (51) 2 (51)
33
(10.1)
28
(8.5)
17
(5.2)
12
(3.7)
10
(3.0)
NA
2-1/2 (64) 2-1/2 (64)
62
(18.9)
60
(18.3)
58
(17.7)
56
(17.1)
55
(16.8)
53
(16.2)
100,000
2Pipeor3-in
Concentric
2-1/2 (64) 2-1/2 (64)
23
(7.0)
15
(4.6)
7
(2.1)
5
(1.5)
NA NA
3 (76) 3 (76)
59
(18.0)
54
(16.5)
49
(14.9)
44
(13.4)
39
(11.9)
34
(10.4)
120,000
2Pipeor3-in.
Concentric
3 (76)† no disk NA
10
(3.)
NA NA NA NA NA
NA 3 (76)†#
43
(13.1)
41
(12.5)
39
(11.9)
37
(11.3)
35
(10.7)
34
(10.4)
4 (102)† no
disk
4† no disk
35
(10.7)
30
(9.1)
25
(7.6)
20
(6.1)
15
(4.6)
10
(3.0)
ALTITUDE ---
FT (M)
UNIT SIZE
(BTUH)
DIRECT VENT (2-PIPE) ONLY
NON-DIRECT
VENT (1-PIPE)
ONLY
NUMBER OF 90° ELBOWS
TERMINATION
TYPE
PIPE DIA
(IN.)*
PIPE DIA (IN.)* 1 2 3 4 5 6
9001 to 10,000‡
(2743 to 3048)
60,000
2Pipeor2-in
Concentric
2 (51) 2 (51)
45
(13.7)
40
(12.2)
38
(11.6)
33
(10.1)
31
(9.4)
29
(8.8)
80,000
2Pipeor2-in
Concentric
2 (51) 2 (51)
30
(9.1)
25
(7.6)
14
(4.3)
9
(2.7)
7
(2.1)
NA
2-1/2 (64) 2-1/2 (64)
57
(17.4)
55
(16.8)
53
(16.2)
51
(15.5)
49
(14.9)
47
(14.3)
100,000
2Pipeor3-in
Concentric
2-1/2 (64) 2-1/2 (64)
21
(6.4)
13
(4.0)
5
(1.5)
NA NA NA
3 (76) 3 (76)
54
(16.5)
49
(14.9)
44
(13.4)
39
(11.9)
34
(10.4)
29
(8.8)
120,000
2Pipeor3-in.
Concentric
NA 3 (76)†#
39
(11.9)
37
(11.3)
35
(10.7)
33
(10.1)
31
(9.4)
29
(8.8)
4 (102)† no
disk
4 (102)† no disk
10
(3.0)
5
(1.5)
NA NA NA NA
* Disk usage --- Unless otherwise specified, use perforated disk assembly (factory-supplied in loose parts bag).
# If one disk is stated, separate 2 halves of perforated disk assembly and use shouldered disk half. When using shouldered disk half, install screen sidetoward
inlet box.
† Wide radius elbow.
‡ Vent sizing for Canadian installations over 4500 ft (1370 M) above sea level are subject to acceptance by the local authorities having jurisdiction.
NA---Not Allowed; pressure switch will not make.
NOTES:
1. Do not use pipe size greater than those specified in table or incomplete combustion, flame disturbance, or flame sense lockout may occur.
2. Size both the combustion---air and vent pipe independently, then use the larger diameter for both pipes.
3. Assume two 45° elbows equal one 90° elbow. Wide radius elbows are desirableandmayberequiredinsomecases.
4. Elbows and pipe sections within the furnace casing and at the vent termination should not be included in vent length or elbow count.
5. The minimum pipe length is 5 ft (1.5 M) for all applications.
6. Use 3-in. (76 mm) diameter vent termination kit for installations requiring 4-in. (102 mm) diameter pipe.
353BAV
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