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UNIT SIZE
ALTITUDE
(BTUH)
60,000
80,000
6001 to 7000
(1829 to 2134)‡
100,000
120,000
UNIT SIZE
ALTITUDE
(BTUH)
60,000
80,000
7001 to 8000
(2134 to 2438)‡
100,000
120,000
UNIT SIZE
ALTITUDE
(BTUH)
60,000
80,000
8001 to 9000
(2438 to 2743)‡
100,000
120,000
UNIT SIZE
ALTITUDE
(BTUH)
60,000
80,000
9001 to 10000
(2743 to 3048)‡
100,000
120,000
* Disk usage ---Unless otherwise stated, use perforated disk assembly (factory ---supplied in loose parts bag).
{ Wide radius elbow.
} Vent sizing for Canadian installations over 4500 ft. (1370M) 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, determine the smallest diameter allowed by the table for each pipe, then use the larger diameter for both pipes.
3. Assume two 45_ elbows equal one 90_ elbow. Long radius elbows are desirable and may be required in some cases.
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. (1.5M) for all applications.
Table 7 — Maximum Allowable Pipe Length --- Ft (M) (Continued)
Direct Vent (2- -Pipe Only)
Termination
Pipe Dia
Type
In. (mm)*
1 ---1/2 (38)
2 Pipe or 2 ---In. (51)
Concentric
2 (51)
1 ---1/2 (38)
2 Pipe or 2 ---In. (51)
Concentric
2 (51)
2 (51)
2 Pipe or 2 ---In. (51)
Concentric
2 ---1/2 (64)
2 Pipe or 3 ---In. (76)
3 (76) one disk†
Concentric
Termination
Pipe Dia
Type
In. (mm)*
1 ---1/2 (38)
2 Pipe or 2 ---In. (51)
Concentric
2 (51)
1 ---1/2 (38)
2 Pipe or 2 ---In. (51)
Concentric
2 (51)
2 (51)
2 Pipe or 2 ---In. (51)
Concentric
2 ---1/2 (64)
2 Pipe or 3 ---In. (76)
3 (76) one disk†
Concentric
Termination
Pipe Dia
Type
In. (mm)*
1 ---1/2 (38)
2 Pipe or 2 ---In. (51)
Concentric
2 (51)
1 ---1/2 (38)
2 Pipe or 2 ---In. (51)
Concentric
2 (51)
2 (51)
2 Pipe or 2 ---In. (51)
Concentric
2 ---1/2 (64)
2 Pipe or 3 ---In. (76)
3 (76) one disk†
Concentric
Termination
Pipe Dia
Type
In. (mm)*
1 ---1/2 (38)
2 Pipe or 2 ---In. (51)
Concentric
2 (51)
1 ---1/2 (38)
2 Pipe or 2 ---In. (51)
Concentric
2 (51)
2 (51)
2 Pipe or 2 ---In. (51)
Concentric
2 ---1/2 (64)
2 Pipe or 3 ---In. (76)
3 (76) one disk†
Concentric
NUMBER OF 90_ ELBOWS
1
2
3
35 (10.7)
30 (9.1)
25 (7.6)
70 (21.3)
70 (21.3)
68 (20.7)
20 (6.1)
15 (4.6)
10 (3.0)
70 (21.3)
70 (21.3)
68 (20.7)
31 (9.4)
26 (7.9)
21 (6.4)
70 (21.3)
70 (21.3)
68 (20.7)
49 (14.9)
48 (14.6)
47 (14.3)
NUMBER OF 90_ ELBOWS
1
2
3
32 (9.8)
27 (8.2)
22 (6.7)
66 (20.1)
65 (19.8)
63 (19.2)
18 (5.5)
13 (4.0)
8 (2.4)
66 (20.1)
65 (19.8)
63 (19.2)
29 (8.8)
24 (7.3)
19 (5.8)
66 (20.1)
65 (19.8)
63 (19.2)
46 (14.0)
44 (13.4)
43 (13.1)
NUMBER OF 90_ ELBOWS
1
2
3
30 (9.1)
25 (7.6)
20 (6.1)
62 (18.9)
60 (17.8)
58 (17.7)
17 (5.2)
12 (3.1)
7 (2.1)
62 (18.9)
60 (18.3)
58 (17.7)
27 (8.2)
22 (6.7)
17 (5.2)
62 (18.9)
60 (18.3)
58 (17.7)
43 (13.1)
41 (12.5)
39 /11.9)
NUMBER OF 90_ ELBOWS
1
2
3
27 (8.2)
22 (6.7)
17 (5.2)
57 (17.4)
55 (16.8)
53 (16.2)
15 (4.6)
10 (3.0)
5 (1.5)
57 (17.4)
55 (16.8)
53 (16.2)
24 (7.3)
19 (5.8)
14 (4.3)
57 (17.4)
55 (16.8)
53 (16.2)
39 (11.9)
37 (11.3)
35 (10.7)
42
4
5
6
20 (6.1)
15 (4.6)
10 (3.0)
67 (20.4)
66 (20.1)
64 (19.5)
5 (1.5)
NA
NA
62
67 (20.4)
57 (17.4)
(18.9)
16 (4.9)
11 (3.4)
6 (1.8)
67 (20.4)
66 (20.1)
64 (19.5)
45 (13.7)
44 (13.4)
43 (13.1)
4
5
6
17 (5.2)
12 (3.7)
7 (2.1)
62 (18.9)
60 (18.3)
59 (18.0)
NA
NA
NA
62 (18.9)
57 (17.4)
52 (15.8)
14 (4.3)
9 (2.7)
NA
62 (18.9)
60 (18.3)
59 (18.0)
41 (12.5)
40 (12.2)
38 (11.6)
4
5
6
15 (4.6)
10 (3.0)
5 (1.5)
56 (17.1)
55 (16.8)
53 (16.2)
NA
NA
NA
56 (17.1)
51 (15.5)
46 (14.0)
12 (3.7)
7 (2.1)
NA
56 (17.1)
55 (16.8)
53 (16.2)
37 (11.3)
35 (10.7)
34 (10.4)
4
5
6
12 (3.7)
7 (2.1)
NA
51 (15.5)
49 (14.9)
47 (14.3)
NA
NA
NA
51 (15.5)
46 (14.0)
41 (12.5)
9 (2.7)
NA
NA
51 (15.5)
49 (14.9)
47 (14.3)
33 (10.1)
31 (9.5)
29 (8.8)
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