508034-02
Issue 2135
Page 24 of 49
Intake Piping
The 95G1UHEX 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 12A through Table 12B 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 25 or 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 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
27) or ventilated crawlspace (Figure 28) the exhaust
vent length must not exceed those listed in Table 13.
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.
INTAKE
DEBRIS
SCREEN
(Provided)
Figure 25. Typical Air Intake Pipe Connections
Upflow Non−Direct Vent Applications
NOTE
- Debris screen and elbow may be rotated, so that screen
may be positioned to face forward or to either side.
(Horizontal Right−Hand Air Discharge Application Shown)
INTAKE
DEBRIS
SCREEN
(Provided)
NOTE -
Debris screen may be positioned straight out (preferred)
or with an elbow rotated to face down.
Figure 26. Typical Air Intake Pipe Connections
Horizontal Non−Direct Vent Applications
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 the maximum volume of
combustion air required for all gas appliances serviced
by this space.
CAUTION