18-CD29D1-11
15
Installer’s Guide
Furnace
Vent
Air
Inlet
(See Note)
For
DIRECT VENT APPLICATION: The Furnaces must
be vented to the exterior of the house and combustion air
MUST come through the inlet air pipe FROM OUTSIDE
AIR.
NOTE:
BAYVENT200* accessories can be used for inlet
and outlet terminals when the pipes do not exit the
structure together.
For Canadian applications, venting systems must meet
ULC-S636 requirements.
For
NONDIRECT VENT APPLICATION: The Furnace
shall be vented to the exterior of the house, but combustion
air may enter from the surrounding area as long as
combustion air requirements are met. (See AIR FOR
COMBUSTION AND VENTILATION)
FURNACE VENT / INLET PIPE INSTALLATION
There are many different variations of the vent / inlet air
pipe combination. The vent / inlet air combination used for
installation of these Furnaces depends on the needs of the
location. However, these guidelines must be followed:
1. The Furnace must vent outside the structure.
2. Furnace combustion air requirements must be met for
non-direct, single pipe applications.
3. For direct vent application of these Furnaces, the vent
pipe and air inlet pipe do not have to exit in the same
air space.
However, the longest individual pipe will
decide the value for the longest allowable equivalent
vent/ inlet air length as shown in the vent length tables
on page 17 and 18.
NOTE: For single pressure zone applications, see Figure
27.
EX. 2 —
The inlet air does not have to come from outside the
structure. Example 2 shows the inlet air, may come from
the attic if the requirements for combustion air are met as
shown in the section AIR FOR COMBUSTION AND VENTI-
LATION.
NOTE: If only the flue gas pipe is to the outside of the
structure, a straight section of pipe (long enough to exit
the Furnace cabinet) must be attached to the inlet air side
with an elbow (which is 5 to 10 equiv. ft.) installed on the
end to prevent dust and debris from falling directly into
the Furnace.
Example 1
Example 2
Furnace
Air
Inlet
Vent
Attic
Vent
(See Note)
The following are
EXAMPLES ONLY:
EX. 1 —
Example 1 shows the vent pipe exhausting through the roof
and the inlet air coming from the interior of the house. The
inlet air coming from the interior of the house must meet
combustion requirements for area, etc., as shown in the sec-
tion AIR FOR COMBUSTION AND VENTILATION in this
Installer’s Guide.
