14 Piping installation
Installation and operation manual
19
RK RKXYQ8T7Y1B
VRV IV compressor unit for indoor installation
4P499900-1A – 2020.10
14
Piping installation
14.1
Preparing refrigerant piping
14.1.1
Refrigerant piping requirements
NOTICE
Refrigerant R410A requires strict cautions for keeping the
system clean and dry. Foreign materials (including mineral
oils or moisture) should be prevented from getting mixed
into the system.
NOTICE
The piping and other pressure-containing parts shall be
suitable for refrigerant. Use phosphoric acid deoxidised
seamless copper for refrigerant.
▪ Foreign materials inside pipes (including oils for fabrication) must
be ≤30 mg/10 m.
14.1.2
Refrigerant piping material
▪
Piping material:
Phosphoric acid deoxidised seamless copper.
▪
Piping temper grade and thickness:
Outer diameter
(Ø)
Temper grade
Thickness (t)
(a)
6.4 mm (1/4")
9.5 mm (3/8")
12.7 mm (1/2")
Annealed (O)
≥0.80 mm
t
Ø
15.9 mm (5/8")
Annealed (O)
≥0.99 mm
19.1 mm (3/4")
22.2 mm (7/8")
Half hard (1/2H)
≥0.80 mm
(a)
Depending on the applicable legislation and the maximum
working pressure of the unit (see "PS High" on the unit name
plate), larger piping thickness might be required.
14.1.3
To select the piping size
Determine the proper size using the following tables and reference
figure (only for indication).
A
a
B
D
D
C
D
D
b
EKEXV
AHU
VRV DX
VRV DX
c
c
a
Heat exchanger unit
b
Compressor unit
c
Refrigerant branch kit
VRV DX
VRV DX indoor unit
EKEXV
Expansion valve kit
AHU
Air handling unit
A
Piping between heat exchanger unit and compressor unit
B
Piping between compressor unit and (first) refrigerant
branch kit (= main pipe)
C
Piping between refrigerant branch kits
D
Piping between refrigerant branch kit and indoor unit
In case the required pipe sizes (inch sizes) are not available, it is
also allowed to use other diameters (mm sizes), taken the following
into account:
▪ Select the pipe size nearest to the required size.
▪ Use the suitable adapters for the change-over from inch to mm
pipes (field supply).
▪ The additional refrigerant calculation has to be adjusted as
mentioned in To determine the additional refrigerant amount.
A: Piping between heat exchanger unit and
compressor unit
Use the following diameters:
Compressor unit
capacity type
Piping outer diameter size (mm)
Gas pipe
Liquid pipe
5 HP
19.1
12.7
8 HP
22.2
B: Piping between compressor unit and first
refrigerant branch kit
Use the following diameters:
Compressor unit
capacity type
Piping outer diameter size (mm)
Gas pipe
Liquid pipe
Standard
Size-up
Standard
Size-up
5 HP
15.9
19.1
9.5
—
8 HP
19.1
22.2
9.5
12.7
Standard ↔ Size-up:
If
Then
The equivalent pipe
length between the
heat exchanger
unit and the
furthest indoor unit
is 90 m or more
5 HP It is
recommended to increase
the
size (size-up) of the
main gas pipe
(between compressor unit and first
refrigerant branch kit). If the
recommended gas pipe (size-up) is not
available, you must use the standard
size (which might result in a small
capacity decrease).
8 HP ▪ You
must increase
the size (size-up)
of the
main liquid pipe
(between
compressor unit and first refrigerant
branch kit).
▪ It is
recommended to increase
the
size (size-up) of the
main gas pipe
(between compressor unit and first
refrigerant
branch
kit).
If
the
recommended gas pipe (size-up) is
not available, you must use the
standard size (which might result in a
small capacity decrease).
C: Piping between refrigerant branch kits
Use the following diameters:
Indoor unit capacity
index
Piping outer diameter size (mm)
Gas pipe
Liquid pipe
<150
15.9
9.5
150≤x<200
19.1
200≤x<260
22.2
D: 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
