Lennox SLP98UHV Installation Instructions Manual page 8

CONDENSATE
TRAP
AIR FLOW
17−1/2 (446) B Width (50W98)
21 (533) C Width (50W99)
24−1/2 (622) D Width (51W00)
FRONT VIEW
NOTE- Optional side return air filter kits are not for use with return air base.
1
Both the unit return air opening and the base return air opening must be covered by a single plenum or IAQ cabinet.
Minimum unit side return air opening dimensions for units requiring 1800 cfm or more of air (W x H): 23 x 11 in. (584 x 279 mm).
The opening can be cut as needed to accommodate plenum or IAQ cabinet while maintaining dimensions shown.
Side return air openings must be cut in the field. There are cutting guides stenciled on the cabinet for the side return air
opening. The size of the opening must not extend beyond the markings on the furnace cabinet.
2
To minimize pressure drop, the largest opening height possible (up to 14 inches) is preferred.
NOTE - Units with 1/2 hp blower motor are equipped with
three flexible legs and one rigid leg. The rigid leg is
equipped with a shipping bolt and a flat white plastic wash­
er (rather than the rubber mounting grommet used with a
flexible mounting leg). See figure 9. The bolt and washer
must be removed before the furnace is placed into op­
eration. After the bolt and washer have been removed, the
rigid leg will not touch the blower housing.
remove shipping bolt and washer
FIGURE 9
Allow for clearances to combustible materials as indicated
on the unit nameplate. Minimum clearances for closet or al­
cove installations are shown in figures 10 and 11.
Optional Return Air Base
(Upflow Applications Only)
FURNACE
FRONT
IF BASE
IS USED
WITHOUT
IAQ CABINET,
INDOOR AIR
A SINGLE
QUALITY
RETURN AIR
CABINET PLENUM
MUST
(PCO, Filter
COVER BOTH
Cabinet, etc.)
UNIT AND
RETURN
AIR BASE
OPENINGS
OPTIONAL
RETURN
AIR BASE
SLP98UHV070V36B and
SL98UH090V036C WITH 1/2 HP
BLOWER MOTOR
RIGID LEG
3−1/4
(83)
1
Unit side return air
5−5/8
7−1/4
(143)
(184)
FIGURE 8
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.
Improper installation of the furnace can result in per­
sonal injury or death. Combustion and flue products
must never be allowed to enter the return air system
or air in the living space. Use sheet metal screws and
joint tape to seal return air system to furnace.
In platform installations with furnace return, the fur­
nace should be sealed airtight to the return air ple­
num. A door must never be used as a portion of the
return air duct system. The base must provide a
stable support and an airtight seal to the furnace. Al­
low absolutely no sagging, cracks, gaps, etc.
For no reason should return and supply air duct sys­
tems ever be connected to or from other heating de­
vices such as a fireplace or stove, etc. Fire, explo­
sion, carbon monoxide poisoning, personal injury
and/or property damage could result.
Page 8
1
23 (584)
Overall
1
(Maximum)
Minimum
11 (279)
Maximum
2
14 (356)
Opening
SIDE RETURN
AIR OPENINGS
(Either Side)
23
(584)
26−7/8
(683)
SIDE VIEW
WARNING
WARNING
1
22−7/16
(570)
Overall
(Maximum)
3/4
(19)