Bryant 351DAS, Installation, Start-Up & Operating Instructions

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Fig. 20—Short Vent (5 to 8 Ft) System
A99025
DOWNFLOW TO SIDEWALL DOWNFLOW TO ROOF
COMBUSTION-AIR PIPE
VENT PIPE
COMBUSTION-AIR PIPE
VENT PIPE
12
″
MIN
12
″
MIN
NOTE: A 12 In. minimum offset pipe section is recommended with
short (5 to 8 ft) vent systems. This recommendation is to reduce
excessive condensate droplets from exiting the vent pipe.
TABLE 7—MAXIMUM ALLOWABLE PIPE LENGTH (FT)
ALTITUDE UNIT SIZE
TERMINATION
TYPE
PIPE DIA
(IN.)*
NUMBER OF 90° ELBOWS
1 2 3 4 5 6
0 to 2000
036080 048080
060080
2 Pipe or 2-In.
Concentric
1-1/2 10 NA NA NA NA NA
2 55 50 35 30 30 20
2-1/2 70 70 70 70 70 70
2001 to 3000
036080 048080
060080
2 Pipe or 2-In.
Concentric
2 49 44 30 25 25 15
2-1/2 70 70 70 70 70 70
3001 to 4000
036080 048080
060080
2 Pipe or 2-In.
Concentric
2 46 41 28 23 22 13
2-1/2 70 70 70 70 70 70
4001 to 5000‡
036080 048080
060080
2 Pipe or 2-In.
Concentric
2 44 39 26 21 20 11
2-1/2 70 70 70 70 70 70
5001 to 6000‡
036080 048080
060080
2 Pipe or 2-In.
Concentric
2 41 36 23 18 17 8
2-1/2 70 70 70 70 70 70
6001 to 7000‡
036080 048080
060080
2 Pipe or 2-In.
Concentric
2 38 33 21 16 15 6
2-1/2 70 70 68 67 66 64
7001 to 8000‡
036080 048080
060080
2 Pipe or 2-In.
Concentric
2 36 31 19 14 12 NA
2-1/2 66 65 63 62 60 59
8001 to 9000‡
036080 048080
060080
2 Pipe or 2-In.
Concentric
2 33 28 17 12 10 NA
2-1/2 62 60 58 56 55 53
9001 to 10,000‡
036080 048080
060080
2 Pipe or 2-In.
Concentric
2 30 25 14 9 7 NA
2-1/2 57 55 53 51 49 47
* Disk usage—Perforated disk assembly (factory-supplied in loose parts bag) MUST BE USED. See Combustion-Air and Vent Pipe Attachment section.
† 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. 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.
—17—