5 Preparation
Installer and user reference guide
13
RXYSCQ4~6TMV1B
VRV IV-S system air conditioner
4P404224-1C – 2019.07
Outdoor unit
capacity type (HP)
Piping outer diameter size (mm)
Gas pipe
Liquid pipe
Standard
Size-up
4+5
15.9
19.1
9.5
6
19.1
22.2
9.5
B: Piping between refrigerant branch kits
Choose from the following table in accordance with the indoor unit
total capacity type, connected downstream. Do not let the
connection piping exceed the refrigerant piping size chosen by the
general system model name.
Indoor unit capacity
index
Piping outer diameter size (mm)
Gas pipe
Liquid pipe
<150
15.9
9.5
150≤x≤182
19.1
Example:
Downstream capacity for B-1 = capacity index of unit 3-1
+ capacity index of unit 3-2
C: Piping between refrigerant branch kit and
indoor unit
Use the same diameters as the connections (liquid, gas) on the
indoor units. The diameters of the indoor units are as follows:
Indoor unit capacity
index
Piping outer diameter size (mm)
Gas pipe
Liquid pipe
15~50
12.7
6.4
63~140
15.9
9.5
D: Piping between refrigerant branch kit and BP
unit
Total capacity index
of connected indoor
units
Piping outer diameter size (mm)
Gas pipe
Liquid pipe
15~62
12.7
6.4
63~149
15.9
9.5
150~182
19.1
9.5
E: Piping between BP unit and RA DX indoor unit
Indoor unit capacity
index
Piping outer diameter size (mm)
Gas pipe
Liquid pipe
15~42
9.5
6.4
50
12.7
60
9.5
71
15.9
5.3.4
To select refrigerant branch kits
For piping example, refer to
"5.3.3 To select the piping size" on
Refnet joint at first branch (counting from outdoor unit)
When using refnet joints at the first branch counted from the outdoor
unit side, choose from the following table in accordance with the
capacity of the outdoor unit.
Example:
Refnet joint A→B‑1.
Outdoor unit capacity type
(HP)
Refrigerant branch kit
4~6
KHRQ22M20T
Refnet joints at other branches
For refnet joints other than the first branch, select the proper branch
kit model based on the total capacity index of all indoor units
connected after the refrigerant branch.
Example:
Refnet joint
B‑1→C‑1.
Indoor unit capacity index
Refrigerant branch kit
<182
KHRQ22M20T
Refnet headers
Concerning refnet headers, choose from the following table in
accordance with the total capacity of all the indoor units connected
below the refnet header.
Indoor unit capacity index
Refrigerant branch kit
<182
KHRQ22M29H
INFORMATION
Maximum 8 branches can be connected to a header.
5.3.5
Refrigerant piping length and height difference
The piping lengths and height differences must comply with the following requirements. Two patterns will be discussed:
• Outdoor with 100% VRV DX indoor units
• Outdoor with 100% RA DX indoor units
Requirement
Limit
VRV DX
RA DX
Maximum actual piping length
▪ Example 1.1, unit 8: a+b+c+d+e+f+g+p≤Limit
▪ Example 1.2, unit 6: a+b+h≤Limit
▪ Example 1.2, unit 8: a+i+k≤Limit
▪ Example 1.3, unit 8: a+i≤Limit
▪ Example 2, unit 18: a+b+m≤Limit
70 m
35 m
Maximum equivalent piping length
(a)
90 m
45 m
Maximum total piping length
▪ Example 1.1: a+b+c+d+e+f+g+h+i+j+k+l+m+n+p≤Limit
▪ Example 2: a+b+c+d+e+f+g+h+i+j+k+l+m≤Limit
300 m
140 m
Minimum length outdoor-first refrigerant branch kit
▪ Example 2: Limit≤a
N/A
5 m
