Lennox G51MP SERIES Installation Instructions Manual page 12

4 − Adjust the outside nut to the appropriate height and
tighten the inside nut to secure the arrangement.
NOTE − The unit may be tilted back−to−front a maximum of
1/2". This will ensure proper draining of the heat exchang-
er.
Leveling Bolt Installation
Furnace Front
3/8
(10)
1−3/4
(44)
Leveling Bolt
Locations
3/8
(10)
1−3/4 (44)
FIGURE 12
Downflow Applications
The unit may be installed three ways in downflow applica-
tions: on non−combustible flooring, on combustible flooring
using an additive base, or on a reverse−flow cooling cabi-
net. Do not drag the unit across the floor in the down-
flow position. Flange damage will result.
Refer to figure 13 for clearances in downflow applica-
tions.
Inches (mm)
3/8
(10)
1−3/4
(44)
Leveling Bolt
Locations
Furnace
Bottom
3/8
(10)
1−3/4
(44)
Downflow Application Installation Clearances
Left Side
Top
*Front
Back
Sides
Vent
Floor
*Front clearance in alcove installation must be 24 in. (610 mm).
Maintain a minimum of 24 in. (610 mm) for front service access.
†Allow proper clearances to accommodate condensate trap and
vent pipe installation.
‡The furnace may be installed on a combustible wood floor if an op-
tional additive base is installed between the furnace and the com-
bustible floor.
Installation on Non−Combustible Flooring
1 − Cut floor opening keeping in mind clearances listed on
unit rating plate. Also keep in mind gas supply connec-
tions, electrical supply, flue and air intake connections
and sufficient installation and servicing clearances.
See table 1 for correct floor opening size.
2 − Flange warm air plenum and lower the plenum into the
opening.
3 − Set the unit over the plenum and seal the plenum to
the unit.
3 − Ensure that the seal is adequate.
NON−COMBUSTIBLE FLOOR OPENING SIZE
Cabinet Width
B Cabinet (17.5")
C Cabinet (21")
D Cabinet (24.5")
Page 12
Top
Right Side
Bottom
0
0
0
0†
0
NC‡
FIGURE 13
TABLE 1
Front to Rear Side to Side
in. mm in.
19 − 3/4 502 16 − 5/8
19 − 3/4 502 20−1/8
19 − 3/4 502 23 − 5/8
mm
422
511
600