Utica Boilers UB90-200 Installationsanweisungen

If concentric vent termination is being used, refer to 

Figure 10 for proper setup.

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

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

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