Reznor RXH (Outdoor PreevA) Unit Installation Manual - Manual (Page 11)

Form I-RDH/REH/RHH/RXH (12-14), P/N 215210 R14, Page 11
5.2.1 Curb Cap Base
The system is equipped with a load-bearing curb cap which forms the integral part of
the unit. The curb cap has bolted seams and is designed so that it may be set directly
on a cement slab, on perpendicular supports, or over a roof curb.
FIGURE 6 - Curb Cap
Base
NOTE: The curb cap
on Models RDH, REH,
RHH, and RXH will not
fit on the same roof curb
as a Reznor ® Model
RGB/RPB. Contact
your distributor about
the availability of a curb
adapter.
5.2.2 Mounting Without a Curb (does not apply to Model RHH)
Prior to installation, be sure that the method of support is in agreement with all local
building codes and is suited to the climate. If considering an installation without a roof
curb in snow areas, it is recommended that the support under the system be at least
12” (305mm) higher than the roof surface. IMPORTANT NOTE: If setting cross sup-
ports on the roof surface and not decking, be sure to have sufficient tread material
under the supports to adequately spread the load and prevent “sinking” into the roofing
material.
The field supplied, weather resistant, cross-support structure must be secure and
adequate for the weight of the system (Refer to weights in Paragraph 5.1). See width
dimensions in Paragraph 4.2.
Cross supports at ends and through
center must be able to support the
weight. A minimum height of 12”
(305mm) is recommended in snow areas.
Unit Bottom
(insulation retainer)
Optional or Field-Supplied
Roof Curb fits inside the
curb cap
MUST be sealed between
curb cap and roof curb
Base of curb cap edge may
be set directly on a cement
slab or on perpendicular
supports.
Wood Nailer
Insulation
6-1/4”
(159mm)
Edge of curb
cap extends
down over
the roof curb.
5.2.3 Mounting on
a Roof Curb - See
FIGURES 8 and 9,
pages 12 and 14 and
follow the instructions
for the model being
installed.
NOTE: If installing a Model RDH or REH unit to replace a Reznor ® Model RGB or
RPB, install a curb adapter on the already installed roof curb. Follow the instructions
provided with the adapter. Seal the top of the adapter before setting the new unit.
The Option CJ curb for a Model RDH, REH, RHH, and RXH unit is a 16” high, fully
enclosed, insulated roof curb. If the application is sound sensitive, consider installing
a field-supplied vibration isolation curb or specialty sound attenuation curb. Whether
using the optional roof curb available with the system or a field-supplied curb, the curb
must be secure, square, and level.
The top surface of the roof curb must be caulked with 1/4” x 1-1/4” sealant tape or two
1/4” beads of suitable sealant. The unit must be sealed to the curb to minimize sound
transmission, prevent air leakage, and to prevent water leakage into the curb area due
to wind blown rain and capillary action.
FIGURE 7 - Mounting a
Unit on Cross Supports