Hitachi RPI-10FSNE - Refrigerant Piping Length Considerations; Calculating Maximum Piping Lengths

18
PMGB0126A rev.2 - 11/2006
REFRIGERANT PIPING &
REFRIGERANT CHARGE
11.4. PIPING AND REFRIGERANT CHARGE
11.4.1. REFRIGERANT PIPING LENGTH
The refrigerant piping between the indoor unit and the outdoor unit should be designed using the following chart. Keep the design
point within the dark area of the chart, wich is showing the applicable height difference according to piping length.
Chart for piping design:
Example in a Single and Twin systems:
Single system Twin system
Maximum piping length according to the unit:
Mark
Unit
Maximum Piping Length
Actual piping length Equivalent piping length
L
RASC-5
≤ 50 m ≤ 70 m
RASC-10
≤ 30 m ≤ 45 m
L = Piping length.
NOTE:
Install the branch pipe at the location from where the piping length to the indoor units is of equal distance. However, when
different piping lengths from the branch pipe to the indoor units, due to building construction are required, the difference
between the two pipes should be as indicate in the table.
System
Unit Pipe
Maximum Piping Length
Actual piping length Equivalent piping length
Twin
RASC-5 A and B
≤ 10 m ≤ 8 m
RASC-10 A - B
≤ 10 m ≤ 8 m
•
•
•
-
L
H
C
B
A
H
L
-H
-H
B
C
A
NOTE:
For Twin system: L=C+(the longest
distance from indoor unit to branch pipe).
-
RASC-10
30
10
0
-20
20
-10
10
20
30
0
L(m)
H(m)
RASC-5
30
10
0
-20
20
-10
10
20
30
40 50
0
L(m)
H(m)