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5020803-UIM-M-0120
DUCTWORK
NOTICE
All units are shipped in the horizontal supply/return configuration. It is
important to reduce the possibility of any air leakage through the bot-
tom duct covers (resulting from cut, torn, or rolled gasket) due to
improper handling or shipping processes. To ensure a good tight
seal, it is recommended that silicone caulk and/or foil tape be applied
along the cover edges.
These units are adaptable to downflow use as well as rear supply and
return air duct openings. To convert to downflow, perform the following
steps:
1. Remove the duct covers found in the bottom return and supply air
duct openings. There are four (4) screws securing each duct cover
(save these screws to use in Step 2).
2. Install the duct covers (removed in step one) to the rear supply and
return air duct openings. Secure with the four (4) screws used in
step one.
3. Seal duct covers with silicone caulk.
Duct work should be designed and sized according to the methods of
the Air Conditioning Contractors of America (ACCA), as set forth in their
Manual D.
Use a closed return duct system. This does not preclude the use of
economizers or ventilation air intake. Flexible duct connectors are rec-
ommended in the supply and return duct work to minimize the transmis-
sion of vibration and noise.
CAUTION
!
When fastening duct work to the side duct flanges on the unit, insert
the screws through the duct flanges only. DO NOT insert the screws
through the casing. Outdoor duct work must be insulated and water-
proofed.
NOTICE
Be sure to note supply and return openings.
Refer to Figures 4 and 5 for information concerning rear and bottom
supply and return air duct openings.
FILTERS
Proper filter size is very important. Filter size, type and pressure drop
should always be considered during duct system design.
Single phase units are shipped without a filter or filter racks. It is the
responsibility of the installer to secure a filter in the return air ductwork
or install a Filter/Frame Kit.
A filter rack and high velocity filters are standard on three phase units.
Filters must always be used and must be kept clean. When filters
become dirt laden, insufficient air will be delivered by the blower,
decreasing your units efficiency and increasing operating costs and
wear-and-tear on the unit and controls.
Check filters monthly. This is especially important because this unit is
used for both heating and cooling.
6
D
16
C
RETURN
A
AIR DUCT
B
SUPPLY
A
AIR DUCT
Model
A
24, 30
10
21.5
36, 42, 48, 60
14
13.5
FIGURE 4: Bottom Duct Dimensions (in.)
SUPPLY
AIR DUCT
15.6
6.75
A
A0344-001
Model
24, 30
36, 42, 48, 60
FIGURE 5: Rear Duct Dimensions (in.)
VIEW LOOKING UP
1.75
AT BOTTOM OF UNIT
F
A0343-001
B
C
D
E
5
4.5
47.5
5
3.5
47.5
RETURN
AIR DUCT
B
A
A
B
9.6
22
13.6
14
Johnson Controls Ducted Systems
E
F
32
42
4.3
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