5 Preparation
Installer and user reference guide
13
5TMV1B
VRV IV-S system air conditioner
4P404224-1 – 2015.03
5.3.4
To select refrigerant branch kits
For piping example, refer to
"5.3.3 To select the piping size" on
page 12
.
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+5
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
<162.5
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
<162.5
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
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
▪ Example 2, unit 18: b+m≤Limit
40 m
40 m
Maximum length outdoor-BP
▪ Example 2, BP3: a+b≤Limit
N/A
30 m
Minimum and maximum length BP-indoor
▪ Example 2, unit 18: Min.≤m≤Max.
Indoor unit capacity index<60
N/A
2~15 m
Indoor unit capacity index=60
N/A
2~12 m
Indoor unit capacity index=71
N/A
2~8 m
Maximum height difference outdoor-indoor
Outdoor higher than indoor
▪ Examples: H1≤Limit
30 m
30 m
Outdoor lower than indoor
Maximum height difference indoor-indoor
▪ Examples: H2≤Limit
15 m
15 m
Maximum height difference outdoor-BP
▪ Example 2: H3≤Limit
N/A
30 m
