Lennox ML193UH Installation Instructions Manual page 8

EQUIPMENT IN CONFINED SPACE - ALL AIR FROM OUTSIDE
(All Air Through Ventilated Attic)
ROOF TERMINATED
EXHAUST PIPE
OUTLET
AIR
SIDE WALL
FURNACE
TERMINATED
EXHAUST PIPE
(ALTERNATE
LOCATION)
NOTE-The inlet and outlet air openings shall each have a free area of
at least one square inch per 4,000 Btu (645mm
of the total input rating of all equipment in the enclosure.
FIGURE 8
EQUIPMENT IN CONFINED SPACE -
ALL AIR FROM OUTSIDE
ROOF TERMINATED
EXHAUST PIPE
SIDE WALL
TERMINATED
EXHAUST PIPE
(ALTERNATE
LOCATION)
NOTE-Each air duct opening shall have a free area of at least one
square inch per 2,000 Btu (645mm
input rating of all equipment in the enclosure. If the equipment room
is located against an outside wall and the air openings communi­
cate directly with the outdoors, each opening shall have a free area
of at least 1 square inch per 4,000 Btu (645mm
hour of the total input rating of all other equipment in the enclosure.
FIGURE 9
Shipping Bolt Removal
Units with 1/2 hp blower motor are equipped with three flex­
ible legs and one rigid leg. The rigid leg is equipped with a
shipping bolt and a flat white plastic washer (rather than the
rubber mounting grommet used with a flexible mounting
VENTILATION LOUVERS
(Each end of attic)
INLET AIR
(Ends 12" above
bottom)
2
per 1.17kW) per hour
OUTLET AIR
FURNACE
INLET AIR
2
per .59kW) per hour of the total
2
per 1.17kW) per
leg). See figure 10. The bolt and washer must be re­
moved before the furnace is placed into operation. Af­
ter the bolt and washer have been removed, the rigid leg
will not touch the blower housing.
Installation - Setting Equipment
WARNING
Do not connect the return air duct to the back of the
furnace. Doing so will adversely affect the operation
of the safety control devices, which could result in
personal injury or death.
Blower access panel must be securely in place when
blower and burners are operating. Gas fumes, which
could contain carbon monoxide, can be drawn into
living space resulting in personal injury or death.
Upflow Applications
The ML193UH gas furnace can be installed as shipped in
the upflow position. Refer to figure 12 for clearances. Se­
lect a location that allows for the required clearances that
are listed on the unit nameplate. Also consider gas supply
connections, electrical supply, vent connection, conden­
sate trap and drain connections, and installation and ser­
vice clearances [24 inches (610 mm) at unit front]. The unit
must be level from side to side. Unit may be positioned from
level to 1/2" toward the front to aid in draining. See figure
11.
Allow for clearances to combustible materials as indicated
on the unit nameplate.
Page 8
ML193UH090P48C
and ML193UH110P48C
with 1/2 HP Blower Motor
RIGID LEG
(Remove shipping bolt
and washer)
FIGURE 10
WARNING