Vii-Accessories - Lennox LGT Series Unit Information

VII-ACCESSORIES

The accessories section describes the application of most
of the optional accessories which can be factory or field
installed to the LGT units.
A-Mounting Frames
When installing units on a combustible surface for down-
flow discharge applications, a C1CURB roof mounting
frame is used. The roof mounting frames are recommend-
ed in all other applications but not required. If the LGT
units are not mounted on a flat (roof) surface, they MUST
be supported under all edges and under the middle of the
unit to prevent sagging. The units MUST be mounted level
within 1/16" per linear foot or 5mm per meter in any direc-
tion.
The assembled C1CURB mounting frame is shown in fig-
ure 27. Refer to the roof mounting frame installation in-
structions for details of proper assembly and mounting.
The roof mounting frame MUST be squared to the roof
and level before mounting. Plenum system MUST be in-
stalled before the unit is set on the mounting frame. Typ-
ical roof curbing and flashing is shown in figure 28. Re-
fer to the roof mounting frame installation instructions for
proper plenum construction and attachment.
ASSEMBLED ROOF MOUNTING FRAME
SUPPLY AIR
OPENING
RETURN AIR
OPENING
FIGURE 27
B-LP / Propane Kit
Natural to LP /propane kit includes a spring kit and three
stickers. In addition, the LP kit contains either six, nine, or
eleven burner orifices. For more detail refer to the natural
to LP gas changeover kit installation instructions.
C-Dirty Filter Switch S27
The dirty filter switch senses static pressure increase indi-
cating a dirty filter condition. The switch is N.O. and clos-
es at 1" W.C. (248.6 Pa) The switch is mounted on the
top filter channel corner. Wiring for the dirty filter switch
is shown on the temperature control section (C2) wiring
diagram in back of this manual.
UNIT BASE
BOTTOM
FIBERGLASS
INSULATION
(Furnished)
NAILER STRIP
(Furnished)
RIGID INSULATION
(Field Supplied)
MOUNTING FRAME
(Extends around entire
perimeter of unit)
D-Transitions
Optional supply/return transitions LASRT08/10 is avail-
able for use with the LGT 7.5 ton units and LASRT10/12
is available for the 8.5 and 10 ton units, utilizing optional
C1CURB roof mounting frames. LGT 12.5 ton units will
use LASRT15 with C1CURB roof mounting frame. Transi-
tion must be installed in the C1CURB mounting frame be-
fore mounting the unit to the frame. Refer to the manufac-
turer's instructions included with the transition for detailed
installation procedures.
E-LAOAD(M) Outdoor Air Dampers (all units)
LAOAD(M) consists of a set of dampers which may be
manually or motor (M) operated to allow up to 25 per-
cent outside air into the system at all times (see figure
29 or 30). Either air damper can be installed in LGT units.
Washable filter supplied with the outdoor air dampers can
be cleaned with water and a mild detergent. It should be
sprayed with Filter Handicoater when dry prior to re-instal-
lation.
F-Supply and Return Diffusers (all units)
Optional flush mount diffuser/return FD11 and extended
mount diffuser/return RTD11 are available for use with all
LGT units. Refer to manufacturer's instructions included
with transition for detailed installation procedures.
G-Blower Proving Switch S52
The blower proving switch monitors blower operation and
locks out the unit in case of blower failure. The switch
is N.O. and closes at .14" W.C. (34.9 Pa) The switch is
mounted on the upper left hand corner of the blower deck.
Wiring for the blower proving switch is shown on the tem-
perature control section (C2) wiring diagram in back of this
manual.
Page 39
TYPICAL FLASHING DETAIL
UNIT BASE
RAIL
COUNTER FLASHING
(Field Supplied)
CANT STRIP
(Field Supplied)
ROOF
ROOFING
MATERIAL
FIGURE 28