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5 Preparation
3 Calculate the refrigerant density using the results of the
calculations in steps 1 and 2 above. If the result of the above
calculation exceeds the maximum concentration level, a
ventilation opening to the adjacent room shall be made.
Formula
F/G≤H
F
Total volume of refrigerant in the refrigerant
system
3
G
Size (m
an indoor unit installed
H
Maximum concentration level (kg/m
4 Calculate the refrigerant density taking the volume of the room
where the indoor unit is installed and the adjacent room. Install
ventilation openings in the door of adjacent rooms until the
refrigerant density is smaller than the maximum concentration
level.
5.3
Preparing refrigerant piping
5.3.1
Refrigerant piping requirements
INFORMATION
Also read the precautions and requirements in the
"General safety precautions" chapter.
NOTICE
The refrigerant R410A requires strict cautions for keeping
the system clean, dry and tight.
▪ Clean and dry: foreign materials (including mineral oils
or moisture) should be prevented from getting mixed
into the system.
▪ Tight: R410A does not contain any chlorine, does not
destroy the ozone layer, and does not reduce earth's
protection against harmful ultraviolet radiation. R410A
can contribute slightly to the greenhouse effect if it is
released. Therefore we should take special attention to
check the tightness of the installation.
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.
5.3.2
Refrigerant piping material
▪ Piping material: Phosphoric acid deoxidised seamless copper.
▪ Piping temper grade and thickness:
Outer diameter
Temper grade
(Ø)
6.4 mm (1/4")
Annealed (O)
9.5 mm (3/8")
12.7 mm (1/2")
15.9 mm (5/8")
Annealed (O)
19.1 mm (3/4")
Half hard (1/2H)
22.2 mm (7/8")
(a)
Depending on the applicable legislation and the unit's
maximum working pressure (see "PS High" on the unit
name plate), larger piping thickness might be required.
Installer and user reference guide
12
) of smallest room in which there is
3
)
(a)
Thickness (t)
Ø
≥0.80 mm
≥0.99 mm
≥0.80 mm
5.3.3
To select the piping size
Determine the proper size referring to following tables and reference
figure (only for indication).
INFORMATION
▪ Combination of VRV DX and RA DX indoor units is not
allowed.
▪ Combination of RA DX and AHU indoor units is not
allowed.
▪ Combination of RA DX and aircurtain indoor units is not
allowed.
INFORMATION
If you install RA DX indoor units, you have to configure
field setting [2‑38] (= type of installed indoor units). See
"7.2.8 Mode 2: Field settings" on
VRV DX
2
B-1
B-2
2
2
C-1
C-2
C-3
3-1
3-2
3-3
1
Outdoor unit
2
Refrigerant branch kits
3-1~3-4
VRV DX indoor units
4
BP units
5
RA DX indoor units
A
Piping between outdoor unit and (first) refrigerant branch
kit
B-1 B-2
Piping between refrigerant branch kits
C-1~C-4
Piping between refrigerant branch kit and indoor unit
D
Piping between refrigerant branch kit and BP unit
E
Piping between BP unit and RA DX 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
"6.7.3 To determine the additional refrigerant
amount" on
page 22.
A: Piping between outdoor unit and (first)
refrigerant branch kit
When the equivalent pipe length between outdoor and indoor units is
90 m or more, the size of the main gas pipe must be increased (size-
t
up). If the recommended gas pipe (size-up) is not available, you
must use the standard size (which might result in a small capacity
decrease).
a
b
a
Outdoor unit
b
Main gas pipe
c
Increase
d
First refrigerant branch kit
e
Indoor unit
page 30.
RA DX
1
A
2
D
D
4
4
C-4
E
E
3-4
5
5
c
e
d
RXYSQ4~6TAY1B
VRV IV-S system air conditioner
4P482257-1 – 2017.03
1
A
E
E
5
5
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