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Figure 14: ZZ15 transition roof curb
Roof curb components
Item
A
Return air
B
Supply air
C
Right side of the unit
D
Front side of the unit
E
2 typ.
F
Insulated deck under the condenser section
G
Insulated deck under the compressor section
Ductwork
You must design and size ductwork according to the methods in
Manual D of the Air Conditioning Contractors of America
(ACCA) or as recommended by any other recognized authority
such as ASHRAE or SMACNA. When you design the duct
system, apply the following recommendations.
• Use a closed return duct system. This does not preclude
the use of economizers or outdoor fresh air intake.
• Make the supply and return air duct connections at the
unit with flexible joints to minimize noise.
• Design the supply and return air duct systems for the CFM
and static pressure requirements of the job. Do not size
them to match the dimensions of the duct connections on
the unit.
See Figure 9 for bottom air duct openings. See Figures 12 and
11, and Table 7 for side air duct openings.
Duct covers
Units are shipped with the side duct openings covered.
For a bottom duct application, no duct cover changes are
necessary.
Johnson Controls Ducted Systems
30-1/2
50-1/2
76-5/8
94
D
Description
E
23 4
A
B
For a side duct application, complete the following steps.
1.
Remove the side duct covers.
2.
Orient the supply panel with the painted surface up.
3.
Slide the supply panel between the heat exchanger and
the unit bottom. The painted surface must face the heat
exchanger. The space is narrow but there is adequate
room to install the panel.
4.
Secure the supply panel with the factory-installed bracket
and two screws.
5.
Orient the return panel with the painted surface down.
6.
Install the return panel over the corresponding side duct.
the painted surface must face the down flow duct opening.
7.
Secure the return panel with four screws.
When you fasten ductwork to the side duct flanges on
the unit, insert the screws through duct flanges only. DO
NOT insert the screws through the casing. You must
insulate and water-proof outdoor ductwork.
80-5/8
26
10
59-1/4
C
64-1/4
5835254-YIM-A-1119
15
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