Installation manual
Page 16 IM-487
Roof Curb Assembly and Installation
Locate the roof curb and unit where the roof can support the
weight. Support the unit to prevent bending or twisting of the
machine. If the building allows sound and vibration into the
occupied space, locate the unit over a non-critical area. It
is the responsibility of the system designer to make ade-
quate provisions for noise and vibration in the occupied
space. Install the curb and unit level to allow the condensate
drain to flow properly with absolutely no pitch away from
the drain. Integral supply and return air duct flanges are pro-
vided with the RAH roof curb, allowing connection of duct-
work to the curb before the unit is set. The gasketed top
surface of the duct flanges seals against the unit when it is set
on the curb. These flanges must not support the total weight
of the ductwork. Refer to “Installing Ductwork” on page 22
for details on duct connections. Assembly of a typical RAH
roof curb is shown in. Parts A through H are common to all
units having bottom return openings. Depending on the unit
length, Parts L and M may be included with the roof curb kit
to create the correct overall curb length.
Figure 14. RAH Roof Curb Assembly Instructions
Figure 15. Roofing Detail "B"
D
Return
Air
F
B
F
E
"X"
Inside
87.00"
(2210 mm)
Inside
90.00"
(2286 mm)
94.75"
(2407 mm)
A
B
E
8.75"
(222mm)
D
See Detail "A"
70.75"
(1797 mm)
C
G
G
C
H
H
A
"Y"
Inside
81.00"
(2057 mm)
Inside
8.75"
(222 mm)
3.50"
(90 mm)
7.50"
(191 mm)
2.00"
(51 mm)
Supply
Air
1. Unit Base
2. Curb Gasketing
3. 2 x 4 Nailer Strip
4. Galvanized Curb
5. Cant Strip (not furnished)
6. Roffing Material (not furnished)
7. Rigid Insulation (not furnished)
8. Counterflashing (not furnished)
9. Flashing (not furnished)
3.50"
(90mm)
Equal Length
Side Supports
L
Using remaining side supports
in this area, align lengths on
opposite sides of assembly
and install a cross support
"D" at each side.
D
M
L
M
Detail A
Main
Unit
Curb
5
9
4
3
7
2
1
8
6
RAH Unit Dimensions In. (mm)
"X" "Y"
047C 38
(965)
28
(711)
077C with Flat Cooling Coil and /or 44"
SWSI Plenum Supply Fan
62
(1575)
38
(965)
077C with Staggered or No Cooling Coil,
and /or 49" SWSI Plenum Supply Fan
62
(1575)
46
(1168)