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Indoor unit capacity
Piping outer diameter size (mm)
index
Gas pipe
<150
150≤x≤176
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
Piping outer diameter size (mm)
index
Gas pipe
15~50
63~140
5.3.4
To select refrigerant branch kits
For piping example, refer to
"5.3.3 To select the piping size" on
page 12.
5.3.5
Refrigerant piping length and height difference
The piping lengths and height differences must comply with the following requirements.
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
Maximum equivalent piping length
Maximum total piping length
▪ Example 1.1: a+b+c+d+e+f+g+h+i+j+k+l+m+n+p≤Limit
Maximum length first branch kit-indoor unit
▪ Example 1.1, unit 8: b+c+d+e+f+g+p≤Limit
▪ Example 1.2, unit 6: b+h≤Limit
▪ Example 1.2, unit 8: i+k≤Limit
▪ Example 1.3, unit 8: i≤Limit
Maximum height difference outdoor-indoor Outdoor higher than indoor
Maximum height difference indoor-indoor
▪ Examples: H2≤Limit
(a)
Assume equivalent piping length of refnet joint=0.5 m and refnet header=1 m (for calculation purposes of equivalent piping length, not for
refrigerant charge calculations).
RXYSQ6T7Y1B9
VRV IV-S system air conditioner
4P404677-1A – 2016.03
Liquid pipe
15.9
9.5
19.1
Liquid pipe
12.7
6.4
15.9
9.5
Requirement
(a)
▪ Examples: H1≤Limit
Outdoor lower than indoor
Example 1 (VRV DX indoor units)
a
b
c
A
B
C
h
i
j
1
2
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)
6
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
<176
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
<176
INFORMATION
Maximum 8 branches can be connected to a header.
Example 1.1
d
e
f
g
H1
D
E
F
G
p
k
l
m
n
3
4
5
6
7
8
H2
5 Preparation
Refrigerant branch kit
KHRQ22M20T
Refrigerant branch kit
KHRQ22M20T
Refrigerant branch kit
KHRQ22M29H
Limit (VRV DX indoor units)
120 m
150 m
300 m
40 m
50 m
40 m
15 m
Installer and user reference guide
13
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Troubleshooting
