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Installer’s Guide
9. The unit should not be exposed to direct roof water runoff.
10. Flexible duct connectors must be of a flame retardant material.
All duct work outside of the structure must be insulated and
weatherproofed in accordance with local codes.
11. Access and service clearances for the unit must be given
careful consideration when locating the duct entrance open-
ings. Figures 1 to 8 provides unit dimensions.
12. Continue with the following installation sections to complete
the installation: Ductwork, Filter, and Electrical Wiring.
Rooftop Installation -- Frame Mounting
For roof top applications using a field fabricated frame and ducts,
use the following procedure:
1. Locate and secure the frame to the roof by bolting or welding.
Add flashing as required. Flashing must conform to local
building codes.
2. Prepare the hole in the roof in advance of installing the unit.
3. Secure the horizontal or down airflow ducts to the roof. Refer
to the previous Convert from Horizontal Airflow to Down Airflow
section if conversion is needed.
4. All fabricated outdoor ducts should be as short as possible.
5. Place the unit on the frame. Refer to Figures 13 or 14.
6. The unit must be mounted level for proper drainage of water
through the holes in the base pan.
7. Secure the unit to the frame.
8. Insulate any ductwork outside of the structure with at least two
(2) inches of insulation and then weatherproof. There must be
a weatherproof seal where the duct enters the structure.
Placing the Unit on the Mounting Curb
1. The unit is designed with a perimeter drip lip that is lower than
the unit base pan, see Figure 11, inset A.
2. Position the unit drip lip down over and in contact with the
outside corner of the curb. See Figure 12, insert A. Continue to
lower the unit on top of the curb, with the unit drip lip astraddle,
and in contact with, both the end and side rail of the curb. The
unit should now rest on top of the curb.
3. Take the two (2) hold-down brackets shipped with the curb and
secure the unit to the curb. See Figure 12, insert A.
Figure 10. Converting Horizontal to Down Airflow
2. Insert the four (4) lifting lugs in the openings provided in the drip
lip on each end of the unit. See Figure 11 insert B. A tap or jerk
to the lug will overcome the interference that arises due to the
dimple on the lug.
3. Before hoisting the unit, be sure that the proper method of
rigging is used with straps or slings and spreader bars for
protection during lifting. Always test-lift the unit to determine the
exact unit balance and stability before hoisting it to the instal-
lation location.
IMPORTANT: Do not lift the unit without test lifting for bal-
ance and rigging. Do not lift the unit in windy conditions or
above personnel. Do not lift the unit by attaching clevis,
hooks, pins, or bolts to the unit casing, casing hardware,
corner lugs, angles, tabs, or flanges. Failure to observe
these warnings may result in equipment damage.
4. When the curb and air ducts have been properly installed, the
unit is ready to be hoisted to the roof and set in position.
IMPORTANT: “Spreader Bars” are recommended when
hoisting the unit.
IMPORTANT: The unit must be lowered into position. The
P.V.C. rubber tape on the curb flange permits the unit to be
repositioned if required without destroying the P.V.C. rubber
seals affixed to the mounting curb.
Note: The ductwork is installed as part of the curb installation.
Do not attach ductwork to the unit and lower the unit with
ductwork onto the curb.
