LG AR-DR12-05A Installation And Operation Manual page 23

Roof Curb Mounting
Roof curb details, including duct locations and dimensions, are to be found in the
roof curb assembly instructions.
Rooftop units require curbs to be mounted first. The duct connections must be locat-
ed so they will be clear of structural members of the building.
Factory-Supplied Roof Curbs
Roof curbs are model GKD which are shipped in a knockdown kit (includes duct
adapters) and require field assembly (by others). Assembly instructions are included
with the curb kit.
Install Curb
Locate curb over roof opening and fasten in place. Check that the diagonal di-
mensions are within ± 1/8 inch of each other and adjust as necessary. For proper
coil drainage and unit operation, it is important that the installation be level. Shim
the curb as required to level. Install gasketing on top surface of curb (provided by
others).
Install Ductwork
Installation of all ducts should be done in accordance with SMACNA and AMCA
guidelines. Duct adapters are provided to support ducts prior to setting the unit.
Set the Unit
Lift unit to a point directly above the curb and duct openings. Guide unit while lower-
ing to align with duct openings. Roof curbs fit inside the unit base. Make sure the unit
is properly seated on the curb and level.
Install Vestibule
If unit was ordered with a vestibule and it has not yet been attached to the unit, caulk
and attach the vestibule at this time.
Optional Piping Vestibule
If the unit was ordered with the vestibule, the NA (Non- Access side) clearance
dimension must be measured from the vestibule.
Ductwork Configurations
Downblast Discharge Ductwork - whenever downblast discharge is used, the
ductwork directly beneath the unit must be connected with either a "T" or an "L" con-
figuration and the area directly beneath the heat source must not have any openings
such as louvers or grates.
Figure 8: Downblast Discharge Ductwork
Due to our policy of continuous product innovation, some specifications may change without notification.
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. "LG" is a registered trademark of LG Corp.
INSTALLATION
Figure 6: Typical Unit with Condensing Section and
Factory Supplied Curb Kit.
Figure 7: Typical Unit with Piping Vestibule and
Factory Supplied Curb Kit.
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