Venting - Lennox SIGNATURE SL280UHV Installation Instructions Manual

Venting

A 4−inch diameter flue transition is factory-installed on the
combustion air inducer outlet of all models. Figure 15
shows the combustion air inducer as shipped from the
factory.
Mounting Screws Location
mounting screw
FIGURE 14
UPFlow Position
UPFLOW POSITION
Top Vent Discharge
flue
transition
pressure
switch
make−up
box
FIGURE 15
IMPORTANT
The unit will not vent properly with the flue transition
pointed down in the 6 o'clock position.
The combustion air inducer may be rotated clock-
wise or counterclockwise by 90° to allow for top or
side vent discharge in all applications. When the unit
is installed, the flue transition must be in the 9
o'clock, 12 o'clock or 3 o'clock position.
If necessary reposition the combustion air inducer, pres-
sure switch and or make up box as needed per the follow-
ing steps and see figures 15 through 21.
mounting screws
vent pipe
collector box
FLOW
AIR
1 − Remove the four mounting screws (figure 14) which
secure the combustion air inducer / pressure switch
assembly to the orifice plate. Lift and rotate the assem-
bly 90 degrees clockwise or counter clockwise to either
the 3 o'clock position or to 9 o'clock position and re−se-
cure with four screws. Gasket should be left in place.
2 − Use tin snips to cut preferred opening on the cabinet
for repositioning the flue outlet. Use the cut out piece
as a cover plate to patch unused opening on cabinet.
UPFLOW POSITION
Left Side Vent Discharge
cover plate
pressure
switch
vent pipe
flue
transition
S
Gas supply piping must be brought into the unit from the right
side in order to accommodate the flue pipe.
S
Remove make−up box assembly (2 screws) and cut wire tie to
free make−up box wires. Re−install make−up box on other side
of cabinet.
S
Re−secure make−up box wires, either pulling excess wires
through the blower compartment and securing with supplied
wire tie, or coil excess wire and secure to the gas manifold.
UPFLOW POSITION
Right Side Vent Discharge
collector box
pressure
switch
make−up
box
S
Pressure switch tubing may be too long. Cut to
fit , then re−attach to barbed fitting on pressure
switch. Tubing must not be allowed to sag.
Page 13
collector box
FLOW
AIR
FIGURE 16
cover plate
flue transition
FLOW
AIR
FIGURE 17
make−up
box
vent pipe