Lennox Merit Series Installation Instructions Manual page 7

A 4−inch diameter ue transition is factory-installed on the
combustion air inducer outlet of all models. Figure 3
shows the combustion air inducer as shipped from the
factory.
Mounting Screws Location
Flue Transition
FIGURE 2
Up ow Position
UPFLOW POSITION
Top Vent Discharge
Flue
Transition
Pressure
Switch
Make−Up
Box
AIR
FIGURE 3
IMPORTANT
The unit will not vent properly with the ue 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 ue 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. See gures 3 through 9.
Mounting Screws
Vent Pipe
Collector Box
FLOW
VENTING
1 − Remove the four mounting screws ( gure 2) which
secure the combustion air inducer / pressure switch
assembly to the ori ce plate. Lift the assembly and ro-
tate it 90 degrees clockwise or counterclockwise to ei-
ther the 3 o'clock position or to 9 o'clock position. Re−
secure with four screws. Gasket should be left in place.
2 − Use tin snips to cut preferred opening on the cabinet
for repositioning the ue outlet. Use the cut−out piece
as a cover plate to patch unused opening on cabinet.
Left Side Vent Discharge
Pressure
Switch
Vent Pipe
Flue
Transition
Gas supply piping must be brought into the unit from the right
side in order to accommodate the ue pipe.
Cut combustion air inducer tubing from 225mm to 125mm
to avoid interference with inducer motor
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.
Re−secure make−up box wires: Either pull excess wires
through the blower compartment and secure using supplied
wire tie, or coil excess wire and secure to the gas manifold.
Right Side Vent Discharge
Cover Plate
Collector Box
Pressure
Switch
Make−Up
Box
Cut combustion air inducer tubing from 225mm to 125mm
to avoid interference with inducer motor
UPFLOW POSITION
Collector Box
FLOW
AIR
FIGURE 4
UPFLOW POSITION
Flue Transition
FLOW
AIR
FIGURE 5
Make−Up
Box
Vent Pipe
7