Chapter 3 — Stack and Intake Vent Sizing and Installation
3-8 Part No. 750-263
For appliances installed in extreme cold climate, it is recommended
that:
1. The stack vent be installed with a slight upward slope of not
more than 1/4" per foot of horizontal run to the vent terminal. In
this case, an approved condensate trap must be installed per
applicable codes.
2. The stack vent is to be insulated through the length of the
horizontal run.
2. Horizontal Thru-Wall Stack Vent Termination
The stack vent cap MUST be mounted on the exterior of the
building. The stack vent cap cannot be installed in a well or below
grade. The stack vent cap must be installed at least one (I) foot
above ground level and above normal snow levels.
Multiple stack vent caps should be installed in the same horizontal
plane with a three (3) foot clearance from the side of one stack cap
to the side of the adjacent stack vent cap(s).
Combustion air supplied from outside must be free of particulate
and chemical contaminants. To avoid a blocked flue condition, keep
all the vent caps clear of snow, ice, leaves, debris, etc.
No substitutions of flue pipe or vent cap material are allowed. Such
substitutions would jeopardize the safety and health of inhabitants.
If the boiler is vented directly out
through the sidewall with no elbows
and less than 6 feet of vent pipe, a
restricted direct vent cap should be
utilized.
The Stainless Steel direct vent cap must be furnished in accordance
with AGA/CSA requirements.
Multiple direct stack vent caps
MUST NOT be installed with one
combustion air inlet directly above
a stack vent cap. This vertical
spacing would allow the flue
products from the stack vent cap
to be pulled into the combustion
air intake installed above. This
type of installation can cause non
warrantable problems with
components and poor operation of
the unit due to the recirculation of
flue products.