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and then add in the equivalent length of each fitting. The
total length, including the equivalent fitting lengths, must
be less than the maximum length specified in Table 2.
Condensing furnace combustion products have very little
buoyancy, so Table 2 is to be used without consideration
of any vertical rise in the piping.
Vent Pipe Installation
CAUTION:
Combustion
air
must
not
be drawn
from
a
corrosive
atmosphere.
This furnace has been certified for installation with zero
clearance between vent piping and combustible surfaces.
However, it is good practice to allow space for convenience
in installation and service.
The quality of outdoor air must also be considered. Be
sure that the combustion air intake is not located near
a source of solvent fumes or other chemicals which can
cause corrosion of the furnace combustion system. (See
list of substances on page 5).
Route piping as direct as possible between the furnace
and the outdoors.
Longer vent runs require larger
diameters. Vent piping must be sloped upwards 1/4"
per foot in the direction from the furnace to the terminal.
This is to ensure that any condensate flows back to the
condensate disposal system.
If a Direct Vent (2-pipe) system is used, the combustion
air intake and the vent exhaust must be located in the
same atmospheric
pressure zone. This means both
pipes must exit the building through the same portion
of exterior wall or roof as shown in Figures 6 - 9 (pages
12- 13)and Figure 37 (page 46).
Piping must be mechanically supported so that its weight
does not bear on the furnace. Pipe supports must be
installed a minimum of every 5 feet along the vent run to
ensure no displacement after installation. Supports may
be at shorter intervals if necessary to ensure that there
are no sagging sections that can trap condensate. It is
recommended to install couplings along the vent pipe,
on either side of the exterior wall (Figure 37). These
couplings may be required by local code.
If breakable connections are required in the combustion
air inlet pipe (if present) and exhaust vent piping, then
straight neoprene couplings for 2" or 3" piping with
hose clamps can be used. These couplings can be
ordered through your local furnace distributor. To install
a coupling:
1. Slide the rubber coupling over the end of the pipe that
is attached to the furnace and secure it with one of
the hose clamps.
2. Slide the other end of the rubber coupling onto the
other pipe from the vent.
3. Secure the coupling with the second hose clamp,
ensuring that the connection is tight and leak free.
Outdoor Terminations
- Horizontal Venting
Vent and combustion
air intake terminations
shall be
installed as depicted in Figures 6 & 7 (page 13) and in
accordance with these instructions:
Vent termination clearances must be consistent with the
NFGC, ANSI 2223.1/NFPA 54 and/or the CSA B149.1,
Natural Gas and Propane Installation Code. Table 17
(page 45) lists the necessary distances from the vent
termination to windows and building air intakes.
All minimum clearances must be maintained to protect
building materials from degradation by flue gases as
shown in Figure 7.
Vent and combustion
air intake terminations
must
be located to ensure proper furnace operation
and
conformance
to applicable
codes. A vent terminal
must be located at least 3 feet above any forced air
inlet located within 10 feet. This does not apply to the
combustion air inlet of a direct vent (two pipe) appliance.
In Canada, CSA B149.1, takes precedence over these
instructions. See Table 17 (page 45).
For optimal performance, vent the furnace through a wall
that experiences the least exposure to winter winds.
The vent termination
shall be located at least 3 ft.
horizontally from any electric meter, gas meter, regulator
and any relief equipment. These distances apply ONLY
to U.S. installations.
In Canada, CSA B149.1, takes
precedence over these instructions.
Do not install the vent terminal such that exhaust is
directed into window wells, stairwells,
under decks
or into alcoves or similar recessed areas, and do not
terminate above any public walkways.
If venting horizontally, a side wall vent kit is available
according to the pipe diameter size of the installation.
For 2 inch pipe use side wall vent kit #904617, and
for 3 inch pipe use kit #904347.
Please follow the
instructions provided with the kit.
Figure 6. Inlet and Exhaust
Pipe Clearances
12
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