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Fig. 7 - - 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.
If electric and control wiring is to be routed through the
basepan, attach the accessory thru- - the- - base service
connections to the basepan in accordance with the
accessory installation instructions.
Slab Mount (Horizontal Units Only) —
Provide a level concrete slab that extends a minimum of
6 inch (150 mm) beyond unit cabinet. Install a gravel
apron in front of condenser coil air inlet to prevent grass
and foliage from obstructing airflow.
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 3 equally spaced 4- - inch
x 4- - inch (102 mm x 102 mm) pads on each side.
Step 5 — Field Fabricate Ductwork
Cabinet return-air static pressure (a negative condition)
shall not exceed 0.35 in. wg (87 Pa) with economizer or
0.45 in. wg (112 Pa) without economizer.
For vertical ducted applications, secure all ducts to roof curb
and building structure. Do not connect ductwork to unit.
Insulate and weatherproof all external ductwork, joints,
and roof openings with counter flashing and mastic in
accordance with applicable codes.
Ducts passing through unconditioned spaces must be
insulated and covered with a vapor barrier.
If a plenum return is used on a vertical unit, the return
should be ducted through the roof deck to comply with
applicable fire codes.
For Units with Accessory Electric Heaters —
All installations require a minimum clearance to
combustible surfaces of 1- - in (25 mm) from duct for first
12- - in (305 mm) away from unit.
MAXIMUM ALLOWABLE
DIFFERENCE IN. (MM)
A-B
B-C
A-C
0.5" (13)
1.0" (25)
1.0" (25)
a50--- 9658
CAUTION
!
PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in damage
to roofing materials.
Membrane roofs can be cut by sharp sheet metal
edges. Be careful when placing any sheet metal parts
on such roof.
Step 6 — Rig and Place Unit
When the unit is ready to be rigged and no longer will be
lifted by a fork truck, the wood protector under the basepan
must be removed. Remove 4 screws from each base rail.
Wood protector will drop to the ground. See instructions on
the unit base rails.
Keep unit upright and do not drop. Spreader bars are
required. Rollers may be used to move unit across a roof.
Level by using unit frame as a reference. See Table 4 and
Fig. 9 for additional information.
Lifting holes are provided in base rails as shown in Fig. 9.
Refer to rigging instructions on unit.
Rigging materials under unit (cardboard or wood) must be
removed PRIOR to placing the unit on the roof curb.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in
equipment damage.
All panels must be in place when rigging. Unit is not
designed for handling by fork truck.
Before setting the unit onto the curb, recheck gasketing on
curb.
Positioning on Curb —
For full perimeter curbs CRRFCURB072A00 and 073A00,
the clearance between the roof curb and the front and rear
1
base rails should be
/
in (6.4 mm). The clearance between
4
the curb and the end base rails should be
retrofit applications with curbs CRRFCURB003A01 and
4A01, the unit should be position as shown in Fig. 8.
1
Maintain the 15
/
in (394 mm) and 8
2
clearances and allow the 22
float if necessary.
Fig. 8 - - Retrofit Installation Dimensions
11
1
/
in (13 mm). For
2
5
/
in (220 mm)
8
5
/
in (567 mm) dimension to
16
C10003
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