76 | LIMITS / PLACEMENT
MULTI V Water 5 Source Unit Engineering Manual
Due to our policy of continuous product innovation, some specications may change without notication.
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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 (maximum 295 feet):
• Pipe segment diameters between the first branch and the last branch must be sized up by one. This applies to both liquid and low pressure
vapor pipes. If the next size up is not available, or if the pipe segment diameters are the same as main pipe (A) diameters, sizing up is not
possible.
• While calculating total refrigerant piping length, pipe (B) segment lengths between the first Y-branch and second Y-branch, and between the
second Y-branch and the heat recovery unit must be calculated by two.
• Length of pipe (C) from each indoor unit to the closest Y-branch, header, or heat recovery unit ≤131 feet.
• [Length of pipe from water source unit to farthest indoor unit (A+B+C)] - [Length of pipe from water source unit to closest indoor unit
(A+B+C)] ≤131 feet.
If the pipe (B) diameters after the rst branch are bigger than the main pipe (A) diameters, pipe (B) must be changed to match main pipe (A)
sizes.
Example: When an indoor unit combination ratio of 120% is connected to a 24-ton water source unit:
Water source unit main pipe (A) diameters: 1-3/8 inches (vapor) and 5/8 inches (liquid).
1. Pipe (B) diameters: 1-3/8 (vapor) and 3/4 (liquid) (after the first branch, when indoor unit combination ratio is 120% [26 tons]).
2. After the rst branch, pipe (B) diameters must be changed to 1-3/8 inches (vapor) and 5/8 inches (liquid) to match main pipe (A) sizes.
Instead of using the total indoor unit capacity to choose main pipe (A) diameters, use water source 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 water source unit.
capacity. Example: When an indoor unit combination ratio of 120% is connected to a 20-ton water source 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 water source unit: 1-1/8 inches (vapor) and 5/8 inches (liquid).
2. Pipe diameters between first and second branches, however, are: 1-3/8 (vapor) and 3/4 (liquid) (connected downstream indoor unit
capacity is 20 tons).
3. If main pipe (A) diameters of a 20-ton water source unit are 1-1/8 (vapor) and 5/8 (liquid), then the pipe diameters between the first
and second branches must be changed to match.
Note that the pipe diameters computed in LATS may not be standard ACR copper tube sizes that are commonly available. In these instances,
refer to the table below and use the next commonly available pipe size. Please refer to the Copper Development Association Inc. Publication
A4015-14/19: Copper Tube handbook for additional information.
PIPING LIMITATIONS
For Systems Designed for Heat Recovery Operation
Following pages present Multi V Water 5 piping limitations and are for illustrative purposes only. Designers MUST use LATS when designing LG VRF
systems.
Table 30: Triple-Frame Connection Pipe Sizes.
Size
(tons)
Water Source
Unit
Voltage Main unit Sub unit 1 Sub unit 2
B
Equivalent pipe length from
WSU to farthest IDU is <295’
Equivalent pipe length from
WSU to farthest IDU is ≥295’
Liquid
(in)
Low
Pressure
Vapor
High
Pressure
Vapor
Liquid
Low
Pressure
Vapor
High
Pressure
Vapor
30 ARWM360BAS5 208-230V ARWM121BAS5 ARWM121BAS5 ARWM121BAS5 3/4” 1-3/8” 1-1/8” 7/8” 1-5/8” 1-1/8”
36 ARWM432BAS5 208-230V ARWM144BAS5 ARWM144BAS5 ARWM144BAS5 3/4” 1-3/8” 1-1/8” 7/8” 1-5/8” 1-1/8”
36 ARWM432DAS5 460V ARWM144DAS5 ARWM144DAS5 ARWM144DAS5 3/4” 1-3/8” 1-1/8” 7/8” 1-5/8” 1-1/8”
40 ARWM504DAS5 460V ARWM192DAS5 ARWM168DAS5 ARWM144DAS5 3/4” 1-3/8” 1-1/8” 7/8” 1-5/8” 1-1/8”
48 ARWM576DAS5 460V ARWM192DAS5 ARWM192DAS5 ARWM192DAS5 3/4” 1-3/8 1-1/8 7/8 1-5/8 1-1/8
Heat Recovery Triple-Frame Connection Pipe Sizes
Table 31: LATS Conditional Piping Upsizing.
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