Step 4 - Provide Unit Support; Roof Curb Mount; Slab Mount (Horizontal Units Only); Alternate Unit Support (In Lieu Of Curb Or Slab Mount) - Carrier WeatherExpert 48LC Installation Instructions Manual

Step 4 — Provide Unit Support
Roof Curb Mount —
Accessory roof curb details and dimensions are shown in
Fig. 8, 9 and 10. Assemble and install accessory roof curb in
accordance with instructions shipped with the curb.
NOTE: The gasketing of the unit to the roof curb is critical
for a watertight seal. Install gasket supplied with the roof
curb as shown in Fig. 8, 9 and 10. Improperly applied
gasket can also result in air leaks and poor unit performance.
Curb should be level. This is necessary for unit drain to
function properly. Unit leveling tolerances are shown in
Fig. 6. Refer to Accessory Roof Curb Installation
Instructions for additional information as required.
A
B
Fig. 6 - - Unit Leveling Tolerances
Install insulation, cant strips, roofing felt, and counter
flashing as shown. Ductwork must be attached to curb and
not to the unit. Thru- - the- - base power connection must be
installed before the unit is set on the roof curb. If
field- - installed thru- - the- - roof curb gas connections are
desired, remove knockout in basepan located in the gas
section; see Fig. 7 for location. Gas connections and
power connections to the unit must be field- - installed after
the unit is installed on the roof curb.
If electric and control wiring is to be routed through the
basepan, remove knockouts in basepan located in control
C
MAXIMUM ALLOWABLE
DIFFERENCE IN. (MM)
A-B B-C A-C
0.25" (6) 0.5" (12) 0.5" (12)
box area of access panel; see Fig. 2, 3, or 4 for basepan
knockout locations for location. Attach the service
connections to the basepan.
Control Box
Access Panel
Filter and
Indoor Coil
Access Panel
Indoor Blower
Access Panel
Gas Heat
Access Panel
Fig. 7 - - Typical Access Panel and Compressor Locations
Slab Mount (Horizontal Units Only) —
Provide a level concrete slab that extends a minimum of
6–in. (150 mm) beyond unit cabinet. Install a gravel apron
in front of condenser coil air inlet to prevent grass and
foliage from obstructing airflow.
C10628
NOTE: Horizontal units may be installed on a roof curb
if required.
Alternate Unit Support (In Lieu of Curb or Slab
Mount) —
A non- - combustible sleeper rail can be used in the unit
curb support area. If sleeper rails cannot be used, support
the long sides of the unit with a minimum of 4 equally
spaced 4- - in. x 4- - in. (102 mm x 102 mm) pads on each
side. Locate pads so that they support the rails. Make sure
to avoid the fork openings.
16
Hood Carton Location
(rear access panel)
Compressor
(each side)
C11154