Carrier 58MTB - Page 38

TABLE 12—MAXIMUM ALLOWABLE PIPE LENGTH (FT) (Continued)
ALTITUDE (FT)
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.)*
123456
7001 to 8000‡
60,000
2 Pipe or 2-in
Concentric
1-1/2 1-1/2 12 7 NA NA NA NA
2 2 53 48 46 41 40 38
80,000
2 Pipe or 2-in
Concentric
2 2 36 31 19 14 12 NA
2-1/2 2-1/2 66 65 63 62 60 59
100,000
2 Pipe or 3-in
Concentric
2-1/2 2-1/2 25 17 8 7 NA NA
3 3 63 58 53 48 43 38
120,000
2 Pipe or 3-in.
Concentric
3† no disk NA 20 13 7 NA NA NA
NA 3† 46 44 43 41 40 38
4† no disk 4† no disk 61 56 51 46 41 36
ALTITUDE (FT)
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.)*
123456
8001 to 9000‡
60,000
2 Pipe or 2-in
Concentric
1-1/2 1-1/2 11 6 NA NA NA NA
2 2 49 44 42 37 35 34
80,000
2 Pipe or 2-in
Concentric
2 2 33 28 17 12 10 NA
2-1/2 2-1/2 62 60 58 56 55 53
100,000
2 Pipe or 3-in
Concentric
2-1/2 2-1/2 23 15 7 5 NA NA
3 3 59 54 49 44 39 34
120,000
2 Pipe or 3-in.
Concentric
3† no disk NA 10 NA NA NA NA NA
NA 3† 43 41 39 37 35 34
4† no disk 4† no disk 35 30 25 20 15 10
ALTITUDE (FT)
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.)*
123456
9001 to 10,000‡
60,000
2 Pipe or 2-in
Concentric
2 2 45 40 38 33 31 29
80,000
2 Pipe or 2-in
Concentric
2 2 30 25 14 9 7 NA
2-1/2 2-1/2 57 55 53 51 49 47
100,000
2 Pipe or 3-in
Concentric
2-1/2 2-1/2 21 13 5 NA NA NA
3 3 54 49 44 39 34 29
120,000
2 Pipe or 3-in.
Concentric
NA 3† 39 37 35 33 31 29
4† no disk 4† no disk 10 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 side toward 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 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.
6. Use 3-in. diameter vent termination kit for installations requiring 4-in diameter pipe.
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