9
Packaged and Split Rooftop Ventilator
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 located so they will be clear of
structural members of the building.
1. 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.
2. Install Curb
Locate curb over roof opening and fasten in place.
Check that the diagonal dimensions 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).
3. 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.
4. Set the Unit
Lift unit to a point directly above the curb and duct
openings. Guide unit while lowering to align with duct
openings. Roof curbs fit inside the unit base. Make sure
the unit is properly seated on the curb and level.
L
W
Typical Unit with Condensing Section and
Factory-Supplied Curb Kit
Ductwork Configurations
NOTE
Downblast Discharge Ductwork
- whenever
downblast discharge is used, the ductwork directly
beneath the unit must be connected with either a “T”
or an “L” configuration and the area directly beneath
the heat source
must not have any openings
such as
louvers or grates.
No louvers or grates
Typical Unit Installed on Rails Supplied by Others
Rail Mounting and Layout
• The units may be installed on rails provided and
installed by others. Ensure that rails are designed to
handle the weight of the unit and provide proper load
distribution on building supports.
• Make sure that rail positioning does not interfere with
the openings on the unit.
• Rails should run the width of the unit and extend
beyond the unit a minimum of 12 inches on each
side.
• Set unit on rails.
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