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Refrigerant Piping
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The following is an example of manual pipe size calculations. Designers are highly encouraged to use LATS instead of manual calculations.
Water Source Unit
Gas Pipe
Main Pipe
Liquid Pipe
Branch Piping
B
IDU
B
Branch Piping
C
C
C
C
IDU
IDU
IDU
IDU
IDU
IDU
B
Branch Piping
Header
Header
C
C
C
A
Table 17: Size of Main Pipe (A) (From Water-Source Unit to Y-branches).
Selecting the Refrigerant Piping
Figure 28:
Selecting Refrigerant Piping.
Example: Five (5) indoor units connected
Water-Source Units (WSU).
IDU: Indoor Units.
A: Main Pipe from Water-Source Unit to Y-branches.
B: Branch Piping.
C: Branch Piping to Indoor Unit (IDU).
Water-Source Unit Capacity (Btu/h)
Liquid Pipe (Inches O.D.)
Gas Pipe (Inches O.D.)
37,500
Ø3/8
Ø5/8
49,500
Ø3/8
Ø5/8
54,600
Ø3/8
Ø3/4
Table 18:
Size of Branch Piping (B) to Branch Piping (B).
Indoor Unit Capacity (Btu/h)
Liquid Pipe (Inches O.D.)
Gas Pipe (Inches O.D.)
19,100
Ø1/4
Ø1/2
54,600
Ø3/8
Ø5/8
76,400
Ø3/8
Ø3/4
Table 19: Size of Branch Piping to Indoor Unit (C).
Indoor Unit Capacity (Btu/h)
Liquid Pipe (Inches O.D.)
Gas Pipe (Inches O.D.)
19,100
Ø1/4
Ø1/2
54,600
Ø3/8
Ø5/8
Pipe Sizing
REFRIGERANT PIPING DESIGN