22
Split Compact Dedicated Outdoor
Air System Installation Manual
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.
REFRIGERANT PIPING SYSTEM INSTALLATION
Figure 11: DOAS Layout Example / Pipe Sizing.
Table 9: Main Pipe A Outside Diameter (O.D.) Sizes (from Outdoor Unit to DOAS Units).
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-
erant system rules, review the information in this entire piping section, see the LG Split Compact DOAS Engineering Manual, and follow the LATS
diagram.
DOAS Layout Example / Selecting the Piping Size
Example: Triple-Frame Multi V 5 Heat Recovery System with
Three (3) DOAS Units Connected
A: Main Pipe from Outdoor Unit to First Y-branch.
B / C / D / E: Pipes from First Y-Branch to Second Y-Branches and /
or Y-Branch to DOAS Units.
•
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•
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Main in a multi-frame system.
• Main heat recovery outdoor unit capacity must be greater than
or equal to the Sub1 heat recovery outdoor unit capacity, and,
where applicable, Sub1 heat recovery outdoor unit capacity must
be greater than or equal to the Sub2 heat recovery outdoor unit
capacity.
• Connection piping from branch to branch cannot exceed the main
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• Install the Y-branches or DOAS units so that the pipe distances
between the between the connected DOAS units are minimized.
Large differences in pipe distances can cause DOAS unit perfor-
mances to fluctuate.
•
Indoor units cannot be connected in a system with DOAS units.
ODU
Capacity
(ton)
Standard Pipe Diameter
Pipe Diameter when Pipe Length is
0D[LPXPIHHW>P@
Liquid Pipe
(inches OD)
Low Pressure Vapor
Pipe (inches OD)
High Pressure Vapor
Pipe (inches OD)
Liquid Pipe
(inches OD)
Low Pressure Vapor
Pipe (inches OD)
High Pressure Vapor
Pipe (inches OD)
10
1/2Ø
1-1/8Ø
3/4Ø
5/8Ø
No Increase
No Increase
12
1/2Ø
1-1/8Ø
7/8Ø
5/8Ø
No Increase
No Increase
14
5/8Ø
1-1/8Ø
7/8Ø
3/4Ø
No Increase
No Increase
16-18
5/8Ø
1-1/8Ø
1-1/8Ø
3/4Ø
No Increase
No Increase
20
5/8Ø
1-3/8Ø
1-1/8Ø
3/4Ø
No Increase
No Increase
22-28
3/4Ø
1-3/8Ø
1-1/8Ø
7/8Ø
No Increase
No Increase
30-42
3/4Ø
1-5/8Ø
1-1/8Ø
7/8Ø
No Increase
No Increase
Table 10: Pipes B / C / D / E Outside Diameters (O.D.) from First Y-Branch to Second Y-Branch and / or Y-Branch to DOAS Unit.
Downstream DOAS Capacity (Btu/h)
Liquid Pipe O.D.
Low Pressure Pipe O.D.
High Pressure Pipe O.D.
3/8 in.
7/8 in.
3/4 in.
1/2 in.
1-1/8 in.
7/8 in.
5/8 in.
1-3/8 in.
1-1/8 in.
3/4 in.
1-5/8 in.
1-3/8 in.