LG Multi V Water IV - Refrigerant Piping Installation: Pipe Sizing for ARWN Heat Pump Systems (Dual-Frame); Dual-Frame System Y-branch and Header Pipe Sizing; Main Pipe (A) Diameter for Y-branch;Header; Refrigerant Pipe (B) Diameter from Y-branch;Header

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MULTI V Water IV System Installation Manual
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Pipe Sizing for ARWN Series Heat Pump Systems
WSU
Capacity
(ton)
Pipe diameter when equivalent pipe
length from WSU to farthest IDU is
<295 ft.
Pipe diameter when equivalent pipe
length from WSU to farthest IDU is
≥295 feet
Liquid pipe
(inches OD)
Vapor pipe
(inches OD)
Liquid pipe
(inches OD)
Vapor pipe
(inches OD)
6 3/8 3/4 1/2 7/8
8 3/8 7/8 1/2 1
10 1/2 1-1/8 5/8 1-1/8
12 1/2 1-1/8 5/8 1-1/8
14 1/2 1-1/8 5/8 1-3/8
16 1/2 1-1/8 5/8 1-3/8
18 3/4 1-3/8 7/8 1-5/8
20 3/4 1-3/8 7/8 1-5/8
24 3/4 1-3/8 7/8 1-5/8
28 3/4 1-5/8 7/8 1-5/8
30 3/4 1-5/8 7/8 1-5/8
32 3/4 1-5/8 7/8 1-5/8
34 3/4 1-5/8 7/8 1-5/8
36 3/4 1-5/8 7/8 1-5/8
40 3/4 1-5/8 7/8 1-5/8
48 3/4 1-5/8 7/8 1-5/8
1
For first branch pipe, use branch pipe that matches main pipe A diameter.
Downstream Total
Capacity of IDUs (Btu/h)
1
Liquid pipe
(inches OD)
Vapor pipe
(inches OD)
≤19,100 1/4 1/2
≤54,600 3/8 5/8
≤76,400 3/8 3/4
≤112,600 3/8 7/8
≤160,400 1/2 1-1/8
≤242,300 5/8 1-1/8
≤354,900 3/4 1-3/8
≤354,900 3/4 1-5/8
Combination Y-branch Pipe and Header Pipe Sizing
When Installing a Dual-Frame System
Example: Five (5) indoor units connected
WSU: Water Source Unit.
IDU: Indoor units.
A: Main Pipe from Water Source Unit
to First Y-branch.
B: Heat Recovery Unit to Heat
Recovery Unit, Y-branch to
Heat Recovery Unit, Heat
Recovery Unit to Header,
or Y-branch to Y-branch.
C: Heat Recovery Unit or Header
to Indoor Unit.
Table 48: Main Pipe (A) Diameter from Water source Unit to First Y-branch / Header Branch.
Table 49: Refrigerant Pipe (B) Diameter from
Y-branch to Y-branch / Header.
Note:
Indoor Unit
Capacity
1
Liquid pipe
(inches OD)
Vapor pipe
(inches OD)
≤19,100 1/4 1/2
≤54,600 3/8 5/8
≤76,400 3/8 3/4
Table 50: IDU Connecting Pipe (C) from Y-Branch.
1
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).
• Larger-capacity water source units must be the
master in a multi-frame system.
• Master water source unit capacity must be greater
than or equal to the slave water source unit capacity.
• Y-branches and other header branches cannot be
installed downstream of the initial header branch.
REFRIGERANT PIPING INSTALLATION
The following is an example of manual pipe size calculations. Designers are highly encouraged to use LATS instead of manual calculations.
Master WSU
Slave WSU
Elevation2:
≤
131 feet
B
C
B
C
≤33 feet
A
Length: ≤492 feet (656 feet conditional application)
ℓ: ≤131 feet (295 feet conditional application)
Elevation1: ≤164 feet
IDU
IDU
Header
IDU
IDU IDU
Brazed Cap
C
Elevation 3:
≤16 feet
Y-branch
(first)
Y-branch
(second)
To indoor units
To WSU
Y-branch
Multi-Frame
Y-branch
Connector
C
C