12 Unit installation
Installation and operation manual
17
LREN8~12A7 + LRNUN5A7
CO
₂
ZEAS outdoor unit and capacity up unit
4P704141-1B – 2022.12
(d)
Calculate h1 and h2 as shown in the figure. Add h1/2 for
maintenance space to the front side. Add h2/2 for maintenance
space to the back side (if wall height exceeds above values).
12.1.2
Additional installation site requirements
of the outdoor unit in cold climates
In heavy snowfall areas it is very important to select an installation
site where the snow will NOT affect the unit. If lateral snowfall is
possible, make sure that the heat exchanger coil is NOT affected by
the snow. If necessary, install a snow cover or shed and a pedestal.
INFORMATION
For instructions on how to install the snow cover, contact
your dealer.
12.1.3
Additional installation site requirements
for CO
₂
refrigerant
NOTICE
Although it is recommended to install LREN* and
LRNUN5* outdoors, in some cases it might be needed to
install them inside. In such cases, ALWAYS follow the
indoor installation site requirements for CO
2
refrigerant.
WARNING
In case of mechanical ventilation, take care the ventilated
air is exhausted to the outdoor space and NOT into
another closed area.
Refrigerant basic characteristics
Refrigerant
R744
RCL (refrigerant concentration limit)
0.072 kg/m
3
QLMV (quantity limit with minimum ventilation)
0.074 kg/m
3
QLAV (quantity limit with additional ventilation)
0.18 kg/m
3
Toxicity limit
0.1 kg/m
3
Safety class
A1
INFORMATION
For more information regarding allowable refrigerant
charge and space volume calculations see the reference
guide of the indoor unit.
Appropriate measures
INFORMATION
Appropriate measures are field supply. Choose and install
all required appropriate measures in accordance with
EN 378-3:2016.
▪ (natural or mechanical) ventilation
▪ safety shut-off valves
▪ safety alarm, in combination with a CO
2
refrigerant leak detector (a
safety alarm alone is NOT considered an appropriate measure
where occupants are restricted in their movements)
▪ CO
2
refrigerant leak detector
WARNING
Install the unit ONLY in locations where the doors of the
occupied space are NOT tight fitting.
WARNING
When using safety shut-off valves, make sure to install
measures such as a bypassing piping with a pressure relief
valve (from liquid pipe to gas pipe). When the safety shut-
off valves close and no measures are installed, increased
pressure may damage the liquid piping.
To determine the minimum number of appropriate
measures
For occupancies other than on the lowest underground floor of
the building
If the total refrigerant charge
(kg) divided by the room
volume
(a)
(m
3
) is…
…the number of appropriate
measures must be at least…
<QLMV
0
>QLMV and <QLAV
1
>QLAV
2
(a)
For occupied spaces with a floor area exceeding 250 m
2
, use
250 m
2
as the floor area for determination of the room volume
(
Example:
even if the room area is 300 m
2
and the room height
is 2.5 m, calculate the room volume as 250 m
2
×2.5 m=625 m
3
)
Example:
Total refrigerant charge in the system is 45 kg and room
volume is 300 m
3
. 45/300=0.15, which is >QLMV (0.074) and
<QLAV (0.18), therefore install at least 1 appropriate measure in the
room.
A (kg)
B (m³)
0
0
100 150
50
200 250
300
350
450
550
400
500
600 650 700 750 800 850 900 950 1000
5
10
15
20
25
30
35
40
45
50
55
60
65
70
c
b
a
QLMV
QLAV
12‒1 Example graph for calculation
A
Refrigerant charge
B
Room volume
a
2 appropriate measures required
b
1 appropriate measure required
c
No measure required
For occupancies on the lowest underground floor of the
building
If the total refrigerant charge
(kg) divided by the room
volume
(a)
(m
3
) is…
…the number of appropriate
measures must be at least…
<RCL
0
>RCL and ≤QLMV
1
>QLMV and <QLAV
2
>QLAV
Value CANNOT be exceeded!
(a)
For occupied spaces with a floor area exceeding 250 m
2
, use
250 m
2
as the floor area for determination of the room volume
(
Example:
even if the room area is 300 m
2
and the room height
is 2.5 m, calculate the room volume as 250 m
2
×2.5 m=625 m
3
)
Example:
Total refrigerant change in the system is 45 kg and room
volume is 300 m
3
. 45/300=0.15, which is >RCL (0.072) and <QLAV
(0.18), therefore install at least 2 appropriate measures in the room.
