![background image](http://html.mh-extra.com/html/carrier/58mtb/58mtb_installation-start-up-and-operating-instructions-manual_2562815037.webp)
5. Clean and dry all surfaces to be joined.
6. Check dry fit of pipe and mark insertion depth on pipe.
7. After pipes have been cut and preassembled, apply generous
layer of cement primer to pipe fitting socket and end of pipe
to insertion mark. Quickly apply approved cement to end of
pipe and fitting socket (over primer). Apply cement in a light,
uniform coat on inside of socket to prevent buildup of excess
cement. Apply second coat.
8. While cement is still wet, twist pipe into socket with 1/4 turn.
Be sure pipe is fully inserted into fitting socket.
9. Wipe excess cement from joint. A continuous bead of cement
will be visible around perimeter of a properly made joint.
10. Handle pipe joints carefully until cement sets.
11. Horizontal portions of the venting system shall be supportive
to prevent sagging support. Support combustion air piping (if
applicable) and vent piping a minimum of every 5 ft (3 ft for
SDR-21 or -26 PVC) using perforated metal hanging strap.
12. Slope combustion air piping (if applicable) and vent piping
downward towards furnace a minimum of 1/4 in. per linear ft
with no sags between hangers.
13. Horizontal portions of the venting system shall be installed so
as to prevent the accumulation of condensate.
14. Use appropriate methods to seal openings where combustion
air pipe (if applicable) and vent pipe pass through roof or
sidewall.
TABLE 12—MAXIMUM ALLOWABLE PIPE LENGTH (FT) (Continued)
ALTITUDE (FT)
UNIT MAX
INPUT RATE
(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
4001 to 5000‡
60,000
2 Pipe or 2-in
Concentric
1-1/2
1-1/2
15
10
5
NA
NA
NA
2
2
64
59
58
53
52
52
80,000
2 Pipe or 2-in
Concentric
2
2
44
39
26
21
20
11
2-1/2
2-1/2
70
70
70
70
70
70
100,000
2 Pipe or 3-in
Concentric
2-1/2
2-1/2
31
22
13
12
NA
NA
3
3
70
70
67
62
57
52
120,000
2 Pipe or 3-in.
Concentric
3† no disk
NA
53
46
40
33
26
20
NA
3†
56
55
54
53
52
52
4† no disk
4† no disk
70
70
70
70
70
70
ALTITUDE (FT)
UNIT MAX
INPUT RATE
(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
5001 to 6000‡
60,000
2 Pipe or 2-in
Concentric
1-1/2
1-1/2
14
9
NA
NA
NA
NA
2
2
60
55
54
49
48
47
80,000
2 Pipe or 2-in
Concentric
2
2
41
36
23
18
17
8
2-1/2
2-1/2
70
70
70
70
70
70
100,000
2 Pipe or 3-in
Concentric
2-1/2
2-1/2
29
21
12
11
NA
NA
3
3
70
67
62
57
52
47
120,000
2 Pipe or 3-in.
Concentric
3† no disk
NA
42
35
29
22
15
9
NA
3†
53
52
50
49
48
47
4† no disk
4† no disk
70
70
70
70
70
70
ALTITUDE (FT)
UNIT MAX
INPUT RATE
(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
6001 to 7000‡
60,000
2 Pipe or 2-in
Concentric
1-1/2
1-1/2
13
8
NA
NA
NA
NA
2
2
57
52
50
45
44
43
80,000
2 Pipe or 2-in
Concentric
2
2
38
33
21
16
15
6
2-1/2
2-1/2
70
70
68
67
66
64
100,000
2 Pipe or 3-in
Concentric
2-1/2
2-1/2
27
19
10
9
NA
NA
3
3
68
63
58
53
48
43
120,000
2 Pipe or 3-in.
Concentric
3† no disk
NA
31
24
18
11
NA
NA
NA
3†
49
48
47
45
44
43
4† no disk
4† no disk
70
70
70
70
67
62
See notes at end of table
37