Dunkirk Q90-200 Series II - Manual (Page 15)

15
If concentric vent termination is being used, refer to
Figure 10 for proper setup.
6 - COMBUSTION AIR/ VENT REQUIREMENTS
Figure 9 - Multiple Boiler Roof Vent/Intake
Terminations
Figure 10 - Sidewall Vent/Intake Terminations
Combustion Air/Vent Pipe Requirements
Boiler requires dedicated direct vent system. Direct vent
system, all air for combustion is taken directly from outside
atmosphere, and all flue products are discharged to outside
atmosphere.
Combustion air and vent pipe connections must terminate
together in same atmospheric pressure zone, either
through roof or sidewall (roof termination preferred). See
Figures 8 and 9 for required clearances.
Venting must be as direct as possible and properly
supported.
12" (305mm)
Minimum
8" (203mm)
Minimum
15" (381mm)
Maximum
3" (76mm)
Minimum
Vent Combustion
Air
12" (305mm)
Minimum Above
Anticipated Snow Line
Vent
3" (76mm)
Minimum
Separation
12" (305mm)
Minimum From
Overhan g
12" (305mm) Separation
Between Bottom of
Combustion Air Intake
And Bottom of Vent
See Snow &
Ice Page 19
Combustion Air
Vent
12" (305mm)
Minimum
Separation
Combustion Air
Figure 11 - Concentric Vent Terminations
Combustion Air
1" (26mm)
Maximum
Maintain 12"
clearance above
highest anticipated
snow level or grade
* See Note
Below
36"(0.9m) Minimum
Maintain 12"(305mm)
Clearance Above Highest
Anticipated Snow Level
or Grade
Canada see page 19
12" (305mm) Minimum
*Must be less than 4" or greater than 24" Horizontal distance
between end bells of each air intake to prevent flue gas recirculation.
Overhang
• Avoid locations where
snow may drift and block
vent and combustion air.
• Ice or snow may cause
boiler to shut down if
vent or combustion air
becomes obstructed.
Vent
Combustion Air
Vent
Single Boiler
Application
Multiple Boiler
Application
Single Boiler
Application
Multiple Boiler
Application