Install Instructions
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IV. Venting B. CPVC/PVC Venting (continued)
• Install Rodent Screen and Vent Terminal
(supplied with boiler), see Figure 10 for
appropriate conguration.
• Brace exterior piping if required.
ii.
Combustion Air Piping
• Locate combustion air termination on the
same roof location as the vent termination
to prevent nuisance boiler shutdowns.
Combustion air terminal can be installed
closer to roof than vent.
• Size roof opening to allow easy insertion
of combustion air piping and allow proper
installation of ashing and storm collar
to prevent moisture from entering the
structure.
- Use appropriately designed vent
ashing when passing through roofs.
Follow flashing manufacturers’
instructions for installation procedures.
- Extend combustion air pipe to maintain
minimum vertical and horizontal
distance of twelve (12) inches from
roof surface. Allow additional
vertical distance for expected snow
accumulation. Provide brace as
required.
- Install storm collar on combustion
air pipe immediately above ashing.
Apply Dow Corning Silastic 732 RTV
Figure 12: Direct Vent - Vertical Terminations
Extend vent/combustion air piping to maintain minimum vertical (‘X’) and minimum horizontal (‘Y’) distance of
twelve (12) inches (18 inches Canada) from roof surface. Allow additional vertical (‘X’) distance for expected
snow accumulation.
Figure 13: Direct Vent - Vertical Terminations
with Sloped Roof
Sealant between combustion air pipe
and storm collar to provide weather-
tight seal.
• Install Rodent Screen and Combustion Air
Terminal (supplied with boiler), see Figure
10 for appropriate conguration.
• Brace exterior piping if required.