196 | GUIDELINES
MUL
TI V Ducted Indoor Unit Engineering Manual
Due to our policy of continuous product innovation, some specifications may change without notification.
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Duct Work For Vertical / Horizontal Air Handler Units
• Use at least ten (10) M4-25L screws when attaching the supply
duct to the vertical-horizontal air handler unit.
• To prevent vibration transmission, install flexible connectors be-
tween the supply duct and the vertical-horizontal air handler unit.
If an electrical heater is included, the flexible connector must be
constructed from a heat-resistant material.
• When routed through unconditioned spaces, ducts must be insulat-
ed and covered with vapor barriers.
• Internal acoustical insulation lining may be necessary for a metal
duct system if it does not have a 90° elbow and ten (10) feet of
main duct to the first branch takeoff.
• Fibrous ducts could be used as a substitute if built and installed
in accordance with the most recent edition of the Sheet Metal and
Air Conditioning Contractors’ National Association (SMACNA)
Construction Standard.
• Fibrous ducts and acoustical linings must follow National Fire
Protection Association (NFPA) Standards 90A or 90B as tested by
UL Standard 181 for Class 1 ducts.
• Seal around the ducts to prevent air leaks.
At least ten (10) screws
(M4-25L)
At least six (6) screws (M-4-25L)
More than
1 inch
Figure 67: Attaching Ducts to the Vertical / Horizontal Air Handler Unit.
Top
Front
Bottom
Right Side
Refrigerant Pipe
Connections
Drain Connections
for Horizontal-Left
Installation
Drain
Connections
for Upflow
Installation
Air Filter Cover
Model No.
Dimensions (inches)
A
B
C
D
E
F G
H
Height Width Depth
NJ Frames
ARNU123NJA4 48-5/8 18 21-1/4 1-9/16 17-1/2 20 17 12-1/8
ARNU183NJA4
ARNU243NJA4
48-5/8 18 21-1/4 1-9/16 17-1/2 20 17 12-1/8
ARNU303NJA4
ARNU363NJA4
NK Frames
ARNU423NKA4
48-5/8 25 21-1/4 1-9/16 24-1/2 20 24 12-1/8
ARNU483NKA4
ARNU543NKA4
Figure 68: Vertical / Horizontal Air Handler Unit Duct Connection
Dimensions Diagram.
Table 154: Vertical / Horizontal Air Handler Unit Duct Connection
Dimensions Table.
General Mounting - Vertical / Horizontal Air Handler Units
APPLICATION GUIDELINES