Lennox ML180UHA Installation Instructions Manual page 10

Horizontal Application
Installation Clearances
Left
End
Bottom
Vent Connector
Type
Top
*Front 57 mm (2-1/4 in.)**
Back
Ends 51 mm (2 in.)
Vent 152 mm (6 in.)
Floor
*Front clearance in alcove installation must be 610 mm (24 in)
Maintain a minimum of 610 mm (24 in.) for front service access.
** 114 mm (4-1/2 in.) if singlewall vent pipe is used.
‡For installations on a combustible floor, do not install the furnace
directly on carpeting, tile or other combustible materials other
than wood flooring.
FIGURE 10
Horizontal Applications
The ML180UHA furnace can be installed in horizontal ap­
plications. Order horizontal suspension kit (51W10) from
Lennox, or use equivalent suspension method.
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or al­
cove installations are shown in figure 10.
This furnace may be installed in either an attic or a crawl­
space. Either suspend the furnace from roof rafters or
floor joists, as shown in figure 11, or install the furnace on a
platform, as shown in figure 12.
Typical Horizontal Application
Unit Suspended in Attic or Crawlspace
FIGURE 11
Top
Right
End
Type C Type B1
0 0
57 mm (2-1/4 in. )
0 0
51 mm (2 in.)
25 mm (1 in. )
0‡ 0‡
Metal
Strap
Internal
Brace
4.8 mm
(3/16 in)
Bracket
Air Flow
NOTE - Heavy-gauge perforated sheet metal straps may
be used to suspend the unit from roof rafters or ceiling
joists. When straps are used to suspend the unit in this
way, support must be provided for both the ends. The
straps must not interfere with the plenum or exhaust pip­
ing installation. Cooling coils and supply and return air
plenums must be supported separately.
NOTE - When the furnace is installed on a platform in a
crawlspace, it must be elevated enough to avoid water
damage and to allow the evaporator coil to drain.
Return Air -- Horizontal Applications
Return air must be brought in through the end of a furnace
installed in a horizontal application. The furnace is
equipped with a removable bottom panel to facilitate
installation. See figure 9.
Horizontal Application
Unit Installed on Platform
Line contact is permissible but not preferred
See the unit nameplate for
clearances.
SERVICE PLATFORM
If this unit is being installed in 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 in­
let 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.
Page 10
GAS
ENTRY
FIGURE 12
CAUTION
VENT
PIPE