Carrier 58MVB Series Product Data page 17

Combustion-air and vent piping for Direct Vent/2-Pipe
(All Sizes) and Non-Direct Vent/1-Pipe (Sizes 040
through 120 Only) Applications
UNIT SIZE
ALTITUDE
(BTUH)
40,000
60,000
8001 to 9000‡
80,000
100,000
120,000
UNIT SIZE
ALTITUDE
(BTUH)
40,000
60,000
9001 to 10000‡
80,000
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 for all applications.
Maximum Allowable Pipe Length (Ft)
DIRECT VENT (2-PIPE) ONLY
Termination Pipe Dia
Type (IN.)*
1-1/2
2 Pipe or 2-In.
Concentric
2
1-1/2
2 Pipe or 2-In.
Concentric
2
1-1/2
2 Pipe or 2-In.
Concentric
2
2
2 Pipe or 2-In.
Concentric
2-1/2
2 Pipe or 3-In.
3†
Concentric
DIRECT VENT (2-PIPE) ONLY
Termination Pipe Dia
Type (IN.)*
1-1/2
2 Pipe or 2-In.
Concentric
2
1-1/2
2 Pipe or 2-In.
Concentric
2
1-1/2
2 Pipe or 2-In.
Concentric
2
2
2 Pipe or 2-In.
Concentric
2-1/2
2 Pipe or 3-In.
3†
Concentric
NON-DIRECT VENT
(1-PIPE) ONLY
Pipe Dia
1
(IN.)*
1-1/2 30
2 62
1-1/2 30
2 62
1-1/2 17
2 62
2 27
2-1/2 62
3 43
NON-DIRECT VENT
(1-PIPE) ONLY
Pipe Dia
1
(IN.)*
1-1/2 27
2 57
1-1/2 27
2 57
1-1/2 15
2 57
2 24
2-1/2 57
3 39
Continued
NUMBER OF 90° ELBOWS
2 3 4 5
25 20 15 10
60 58 56 55
25 20 15 10
60 58 56 55
12 7 NA NA
60 58 56 51
22 17 12 7
60 58 56 55
41 39 37 35
NUMBER OF 90° ELBOWS
2 3 4 5
22 17 12 7
55 53 51 49
22 17 12 7
55 53 51 49
10 5 NA NA
55 53 51 46
19 14 9 NA
55 53 51 49
37 35 33 31
6
5
53
5
53
NA
46
NA
53
34
6
NA
47
NA
47
NA
41
NA
47
29
17