Lennox SL280UHNX Series Unit Information page 46

Multiple Venting
The SL280UHV(X) furnace can vent in multiple positions.
See FIGURE 18.
The make up box may be removed and the combustion
air inducer may be rotated clockwise or counterclockwise
90° to allow for vertical or horizontal vent discharge in a
vertical or horizontal cabinet position.
vent pipe
vent pipe
flue
transition
In all positions route the wires away from moving parts and the heat of the inducer
motor to prevent damage to the wires. The pressure switch must be installed above
the CAI to prevent moisture from collecting in the hoses or switch.
FLOW
AIR
vent pipe
flue transition
AIR
FLOW
Remove the four mounting screws, rotate the assembly
(assembly consists of orifice plate, proving switch, gasket
and combustion air inducer), then reinstall the mounting
screws. See unit Installation Instructions for more detail.
The combustion air pressure switch must be moved
for horizontal discharge air left position.
vent pipe
vent pipe
flue
transition
vent pipe
pressure switch
FIGURE 18
Page 46
IMPORTANT
vent pipe
AIR
FLOW