Multiple Boiler Venting Installation - Dunkirk DKVLT-050 Installation, Operation & Maintenance Manual

6.8 Multiple Boiler Venting Installation

• Multiple boiler application boiler can vent individually or
use common vent pipes.
• If boilers vent individually follow guidelines as described
in figures 6-1 through 6-7.
• If boilers vent through common vent pipes, as shown
in Figure 6-17, choose common vent pipe per Table 8.
Choose size from Table 9 for pipes between boiler and
common vent pipes.
• Longest individual vent lengths and common vent length
together must be shorter than 100 ft. (30m).
H + L ≤ 100 ft (30m) (See Table 9)
• Each boiler must have flow check valve to prevent flue
gas back flow.
• External terminals follow same rule as single boiler
venting as described in Section 6.6 and 6.7
• Locate combustion air and vent terminals as required by
authority having jurisdiction.
FIGURE 6-17 Mulitple Boilers With Common Venting Pipe
H
Flow Check
Valve
6 - COMBUSTION AIR AND VENT PIPING
L
Flow Check
Valve
32
Table 8 - Minimum Diameter for Individual
Boiler in Common Venting System
Model
050
075
100
150
200
299
Table 9 - Common Venting Pipe Diameters
Minimum
Diameter of
Total
Common vent
Firing
pipes if
Rate
L< 50 ft (16m)
400 4" (101mm)
600
5" (127mm)
800
1000
1200 6" (152mm)
1400
1600
1800 7" (177mm)
2000
Flow Check
Valve
Minimum
Diameter
2" (51mm)
3" (73mm)
3" (73mm)
3" (73mm)
3" (73mm)
3" (73mm)
Minimum
Diameter of
Common vent
pipes if
L>50 ft (16m)
5" (127mm)
6" (152mm)
7" (177mm)
8" (203mm)
Vent
Combustion
Air
Minimum 12" (305mm)
U.S. ; 18" (457mm)
Canada Above
Anticipated Snow Line
Ground Level
P/N 240011326, Rev. B [04/15/2016]
Snow Line