Page 28
Intake Piping
The ML196DFE furnace may be installed in either
direct
vent or non-direct vent applications.
In non-direct vent
applications, when intake air will be drawn into the furnace
from the surrounding space, the indoor air quality must be
considered. Guidelines listed in Combustion, Dilution and
Ventilation Air section must be followed.
Follow the next two steps when installing the unit in
Direct
Vent
applications, where combustion air is taken from out
-
doors and flue gases are discharged outdoors.
The pro-
vided air intake screen must not be used in direct vent
applications (outdoors).
Use cement to secure the intake pipe to the inlet air
connector.
2 - Route piping to outside of structure. Continue with
installation following instructions given in general
guide lines for piping terminations and intake and
exhaust piping terminations for direct vent sections.
Refe to TABLE 13 for pipe sizes.
Follow the next two steps when installing the unit in
Non-
Direct Vent applications
where combustion air is taken
from indoors and flue gases are discharged outdoors.
Use field-provided materials and the factory-provided
air intake screen to route the intake piping as shown
in FIGURE 26. Maintain a minimum clearance of 3”
(76mm) around the air intake opening. The air intake
opening (with the protective screen) should always be
directed forward, or sideways.
2 - If intake air is drawn from a ventilated attic (FIGURE
27) or ventilated crawlspace (FIGURE 28) the exhaust
vent length must not exceed those listed in TABLE
14. If 3” diameter pipe is used, reduce to 2” diameter
pipe at the termination point to accommodate the
debris screen.
3 - Use cement to secure the intake pipe to the connector,
if desired.
TYPICAL AIR INTAKE PIPE CONNECTIONS
NON−DIRECT VENT APPLICATIONS
AIR
INTAKE
SCREEN
(Provided)
NOTE
- Air intake screen and elbow may be rotated, so that
screen may be positioned to face forward or to either side.
FIGURE 26
CAUTION
If this unit is being installed in an application with
combustion air coming in from a space serviced by
an exhaust fan, power exhaust fan, or other device
which may create a negative pressure in the space,
take care when sizing the inlet air opening. The
inlet air opening must be sized to accommodate
the maximum volume of exhausted air as well as
themaximum volume of combustion air required for
all gas appliances serviced by this space.
