Lennox EL195UH040NE36B Installation Instructions And Use page 22

Intake Piping
The EL195UHNE 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 and 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
outdoors and flue gases are discharged outdoors. The
provided air intake screen must not be used in direct
vent applications (outdoors).
1 - Use transition solvent cement or a sheet metal screw
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
guidelines for piping terminations and intake and
exhaust piping terminations for direct vent sections.
Refer to table 5 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.
1 - Use field-provided materials and the factory-provided
air intake screen to route the intake piping as shown
in figure 28 or 29. 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 to either side in the
upflow position, and either straight out or downward
in the horizontal position. The air intake piping must
not terminate too close to the flooring or a platform.
Ensure that the intake air inlet will not be obstructed
by loose insulation or other items that may clog the
debris screen.
2 - If intake air is drawn from a ventilated attic (figure
30) or ventilated crawlspace (figure 31) the exhaust
vent length must not exceed those listed in table 6. If
3" diameter pipe is used, reduce to 2" diameter pipe
at the termination point to accommodate the debris
screen.
3 - Use a sheet metal screw to secure the intake pipe to
the connector, if desired.
TYPICAL AIR INTAKE PIPE CONNECTIONS
NOTE - Debris screen and elbow may be rotated, so that
screen may be positioned to face forward or to either side.
TYPICAL AIR INTAKE PIPE CONNECTIONS
HORIZONTAL NON−DIRECT VENT APPLICATIONS
(Horizontal Right−Hand Air Discharge Application Shown)
NOTE - Debris screen may be positioned
with elbow rotated to face down or face up.
Page 22
UPFLOW NON−DIRECT
VENT APPLICATIONS
Figure 28
Figure 29
INTAKE
DEBRIS
SCREEN
(Provided)
INTAKE
DEBRIS
SCREEN
(Provided)