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Section 7:
Unit Placement:
Figure 6: Roof Curb Installation
7.1 Roof Installation on Curb
Roof curbs are available for units that are to be installed
on a typical flat roof (ie. bonded or corrugated) with no
seismic restraint requirements. (If seismic restraint is
required, contact factory.) Curb dimension and weight
information is available in the PR Selection Software, ACE
Interface. Note: Before installation, verify that you have
the correct roof curb and that all required components
are present.
7.2 Roof Curb Assembly and Installation
Place the curb on the roof in the position in which it will
be installed. Check that the diagonal measurements
are within 1/16”(1.6 mm) of each other. To ensure a
weatherproof seal between the unit and the curb, the curb
must be level with no twist from end to end. Shim level as
r
equired and secure curb to roof deck using best building
practices. Inspect curb to ensure that none of the field
piping routed through the curb protrude above the curb.
Install roofing material as required.
NOTE: Check the installation location to ensure proper
clearances to combustibles and clearance for access.
7.3 Unit Mounting to Roof Curb
After the curb has been installed, the unit may be placed
on the curb. All PR units are supplied with a closed cell
neoprene insulation on the underside of the unit. This will
seal the top of the curb and the base surface of the unit to
prevent moisture from leaking into the building (ie. from
driving rains or melting snow.) The installer is responsible
for attaching the unit to the curb per all applicable codes.
7.4 Unit Mounting to Ground Pad
When installed at ground level, the unit should be
mounted on a level concrete slab which should extend at
least 2” (5.1 cm) beyond the unit on all sides. The top of
the slab should be 2” (5.1 cm) above the ground level. The
depth of the slab below the ground level and its structural
design is governed by the type of soil and climatic
conditions. The slab must not be in contact with any part
of the building wall or foundation. The space between
the slab and the building wall prevents the possibility of
transmitting vibration to the building.
2” x 4” (5cm x 10cm) Treated Wood
Nailer With Curb
3/8” (0.95cm) x 2” (5.1 cm) Closed Cell
Neoprene Insulation (Factory Installed)
Butyl Caulk Seal (Field Supplied)
Bottom Pan
12 Gauge Channel
E Cabinet - 8” (20.3cm)
14” (35.6cm)
Counter Flashing & Cant Strip,
Field Supplied
1/2” (1.3 cm) Nom.
Rigid Insulation
Field Supplied
Unit
A - D Cabinet - 6.5” (16.5cm)
PR Series Installation, Operation, and Maintenance Manual
