
32
MUL
TI V W
ater Mini System Installation Manual
Due to our policy of continuous product innovation, some specifications may change without notification.
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Pipe Sizing
REFRIGERANT PIPING DESIGN
The following is an example of manual pipe size calculations. Designers are highly encouraged to use LATS instead of manual calculations.
1
For calculation purposes, assume equivalent pipe length of Y-branch is 1.6 feet, and equivalent pipe length of header is 3.3 feet.
Length
Total pipe length
Longest actual pipe length
Longest Equivalent pipe length
1
A + ΣB + ΣC + D ≤475.7 feet
A + B + D ≤230 feet
A + B + D ≤295.2 feet
ℓ
Longest pipe length after first branch
B + D ≤ 131 feet
Elevation1
Elevation differential (Water-source unit ↔ Indoor unit)
≤ 98.4 feet
Elevation2
Elevation differential (Indoor unit ↔ Indoor unit)
≤ 49 feet
Distance between fittings and indoor units
≥20 inches
Distance between fittings and
Y-Branches
≥20 inches
Distance between two Y-Branches
≥20 inches
Distance between Header and indoor units
≥20 inches
Table 15:
Pipe Capabilities.
Example: Five (5) indoor units connected
Water-Source Units (WSU).
IDU: Indoor Units.
Y-branches.
Header.
A: Main Pipe from First Y-branch.
B: Pipe from Y-branch to Y-branch or Header.
C: Pipe from Y-branch or Header to Indoor Unit.
D: Pipe to Farthest Indoor Unit.
System Using Y-branches and Header
Length: ≤230 feet
ℓ: ≤131 feet
Elevation1: ≤98.4 feet
Elevation2: ≤49 feet
Water Source Unit
Header
First Y-branch
Second Y-branch
B
Brazed Cap
IDU
IDU
C
D
C
C
C
IDU
IDU
Y-branch
To Water
Source
Unit
To Indoor
Units
IDU
Downstream Total Capacity of IDUs (Btu/h) Liquid Pipe (Inches O.D.)
Vapor Pipe (Inches O.D.)
≤19,100
Ø1/4
Ø1/2
< 54,600
Ø3/8
Ø5/8
≤76,400
Ø3/8
Ø3/4
Table 16: Refrigerant Pipe Diameter (B) from Y-branch to Y-branch / Header.
• Indoor units should be installed at a lower
position than the Header.
• Y-branch pipes cannot be used after
Headers.
•
Install the Header so that the pipe dis
-
tances between the between the con-
nected indoor units are minimized. Large
differences in pipe distances can cause in-
door unit performances to fluctuate.
•
Always reference the LATS Multi V software
report.
Note:
•
Connection piping from branch to branch cannot exceed the main pipe diameter (A) used by the water-source unit.
• Y-branches and other header branches cannot be installed downstream of the initial header branch.
Note: