LG ARUM072BTE5 Installation Manual page 61

Table 30: Pipe Diameters (B) from Y-branch to Y-branch / Header.
Downstream Total Capacity of IDUs (Btu/h)
≤19,100
≤54,600
≤76,400
≤114,700
≤172,000
≤229,400
≤248,500
≤344,000
≤592,500
For the first branch pipe, use the branch pipe that matches main pipe A diameter.
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Table 31: Indoor Unit Connecting Pipe from Branch (C).
Indoor Unit Capacity
1
≤19,100
≤54,600
≤76,400
9,600-24,200 Btu/h 4-way 3 feet x 3 feet Cassette and 15,400-24,200 Btu/h High Static Ducted indoor units have 3/8Ø (liquid) and 5/8Ø (vapor).
1
Conditional Applications
Conditional applications are computed in LATS. See below for an explanation of when pipes are upsized.
If the equivalent length between the first Y-branch to the farthest indoor unit is >131 feet (up to 295 feet maximum):
• Pipe segment diameters between the first Y-branch and the second Y-branch must be sized up by one. This applies to both liquid and vapor
pipes. If the next size up is not available, or if the piping segment diameters are the same as main pipe (A) diameters, sizing up is not
possible.
• While calculating the entire refrigerant pipe length, pipe lengths for ΣB must be multiplied by two: A+(ΣBx2)+ΣC ≤3,281 feet.
• Length of pipe (C) from each indoor unit to the closest Y-branch or header ≤ 131 ft.
• [Length of pipe from outdoor unit to farthest indoor unit (A+B+C)] - [Length of pipe from outdoor unit to closest indoor unit (A+B+C)] ≤131
feet.
If the pipe (B) diameters after the first branch are bigger than the main pipe (A) diameters, pipe (B) must changed to match main pipe (A)
sizes.
Example: When an indoor unit combination ratio of 120% is connected to a 22-ton outdoor unit:
Outdoor unit main pipe (A) diameters: 1-3/8Ø inches (vapor) and 5/8Ø inches (liquid).
1. Pipe (B) diameters: 1-3/8Ø (vapor) and 3/4Ø (liquid) (after the first branch, when indoor unit combination ratio is 120% [26 tons]).
2. After the first branch, pipe (B) diameters must be changed to 1-3/8Ø inches (vapor) and 5/8Ø inches (liquid) to match main pipe (A)
sizes.
Instead of using the total indoor unit capacity to choose main pipe (A) diameters, use outdoor unit capacity to choose downstream main pipe
(A) diameters. Do not permit connection pipes (B) from branch to branch to exceed main pipe (A) diameters as indicated by outdoor unit
capacity. Example: When an indoor unit combination ratio of 120% is connected to a 20-ton outdoor unit (24 tons), and indoor unit with a
7,000 Btu/h capacity is located at the first branch:
1. Main pipe (A) diameters on a 20-ton outdoor unit: 1-1/8Ø inches (vapor) and 5/8Ø inches (liquid).
2. Pipe diameters between first and second branches, however, are: 1-3/8Ø (vapor) and 3/4Ø (liquid) (connected downstream indoor unit
capacity is 20 tons).
3. If main pipe (A) diameters of a 20-ton outdoor unit are 1-1/8Ø (vapor) and 5/8Ø (liquid), then the pipe diameters between the first and
second branches must be changed to match.
INSTALLING FOR HEAT PUMP
Liquid pipe (inches OD)
Liquid pipe (inches OD)
1/4Ø
3/8Ø
3/8Ø
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.
1/4Ø
3/8Ø
3/8Ø
3/8Ø
1/2Ø
5/8Ø
5/8Ø
3/4Ø
3/4Ø
Vapor pipe (inches OD)
1/2Ø
5/8Ø
3/4Ø
OPERATION
Sample Layouts
Vapor pipe (inches OD)
1/2Ø
5/8Ø
3/4Ø
7/8Ø
1-1/8Ø
1-1/8Ø
1-3/8Ø
1-3/8Ø
1-5/8Ø
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