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d
Remote controller NOT compatible with R32 safety
system
e
Remote controller compatible with R32 safety system
f
Remote controller in supervisor mode
g
Supervisor room
NOT allowed
Allowed
13.4.3
Natural ventilation
Natural ventilation is a safety measure where ventilation is made to a
place where sufficient air is available to dilute the leaked refrigerant
such as a large space.
The natural ventilation safety measure can be applied by following
the steps below:
Step 1 – Determine total room area, which is the total area of the
space that has natural ventilation and the space in which the indoor
unit is installed:
The respective room area can be determined by projecting the walls,
doors and partitions to the floor and calculating the enclosed area.
Spaces connected only through false ceilings, ductwork, or similar
connections are not considered a single space.
Step 2 – Use the graph or table below to determine the total
refrigerant charge:
250
240
230
220
210
200
190
180
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
0
5
10
15
20
25
30
35
40
m [kg]
m
Total refrigerant charge in the system [kg]
A
Area of the room with natural ventilation [m²]
1
A
Minimum room area of the space in which the indoor unit
min
is installed [m²]
Note: Round down the derived values.
The graphs and table are based on an installation height of the
indoor unit between 1.8 m and 2.2 m (bottom of indoor unit or bottom
of duct openings).
If the installation height is more than 2.2 m, higher total refrigerant
charge limit of the system can apply. To know the total refrigerant
charge limit of the system in case the installation height is more than
2.2 m, refer to the online tool
(VRV
Step 3 – The total amount of refrigerant in the system MUST be less
than the refrigerant charge limit derived from the graph above. If
NOT, natural ventilation safety measure is not allowed.
Step 4 – The partition between two rooms on the same floor MUST
meet one of the following two requirements for natural ventilation.
1
Rooms on the same floor that are connected with a permanent
opening that extends to the floor and is intended for people to
walk through.
2
Rooms on the same floor connected with permanent openings
that fulfil the requirements listed below. The openings must
consist out of two parts to allow air circulation for natural
ventilation.
RXYSA8~12AMY1B
VRV 5-S system air conditioner
4P752781-1B – 2024.02
A
+ A
m
[m²]
1
min
0
10
20
30
10.1
40
13.5
50
16.8
60
20.2
70
23.6
80
27.0
90
30.3
100
33.7
110
37.1
120
40.5
130
43.9
140
47.2
150
50.6
160
54.0
170
57.4
180
60.7
190
64.1
200
67.5
210
70.9
220
74.2
230
77.6
236
79.6
237
79.8
45
50
55
60
65
70
75
80
240
79.8
250
79.8
Xpress).
13 Special requirements for R32 units
A
≤ 100 mm
A
Minimal natural ventilation area
nvmin
For the lower opening:
▪ It is not an opening to the outside
▪ The opening cannot be closed
▪ The opening must be ≥0.012 m² (A
▪ The area of any openings above 300 mm from the floor does
not count when determining A
[kg]
▪ At least 50% of A
0
3.3
6.7
▪ The bottom of the lower opening is ≤100 mm from the floor
▪ The height of the opening is ≥20 mm
For the upper opening:
▪ It is not an opening to the outside
▪ The opening cannot be closed
▪ The opening must be ≥0.006 m² (50% of A
▪ The bottom of the upper opening must be ≥1500 mm above the
floor
▪ The height of the opening is ≥20 mm
Note: The requirement for the upper opening can be met by false
ceilings, ventilation ducts or similar arrangements that provide an
airflow path between the connected rooms.
Example
The total amount of refrigerant in the VRV system is 20 kg. The VRV
system has two indoor units which are installed in a space that does
not belong to the lowest underground floor of the building. The space
in which the indoor units are installed has a room area of 25 m². An
adjacent room has a room area of 45 m² to which air circulation is
possible through a partition that meets one of the two requirements
in the above text. The safety measure chosen is Alarm + Natural
ventilation (based on the total amount of refrigerant and room area
from the graph for "All other floors").
1 To apply the Alarm safety measure, see "13.4.2 Alarm" [ 4 21].
2 In addition, apply the Natural ventilation safety measure: total
room areas of installed room and adjacent room where natural
ventilation can be made: 25 m²+45 m²=70 m²
▪ Total refrigerant charge limit for the system determined using
the graph for natural ventilation is 23.6 kg.
Total amount of refrigerant in the system (20 kg) < Total refrigerant
charge limit (23.6 kg), which means that the safety measure can be
applied.
≥ 20 mm
≥ 20 mm
nvmin
≥ 50% A
nvmin
)
nvmin
nvmin
is less than 200 mm above the floor
nvmin
)
nvmin
Installation and operation manual
23
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