Hitachi YUTAKI RWM-2R1E Installation & Operation Manual page 69

REFRIGERANT AND WATER PIPING
The minimum volume of a closed room where the system is installed to avoid suffocation in case of leakage is:
The formula used for the calculation of the maximum allowed refrigerant concentration in cases of refrigerant leakage is the
following:
R
— = C
V
If the room volume is below the minimum value some effective measure must be taken into account after installing to prevent
suffocation is case of leakage.

Countermeasure in the event of possible refrigerant leakage
The room must have the following features to prevent suffocation in case a refrigerant leakage occurs:
1 Provide a shutterless opening which will allow fresh air to circulate into the room.
2 Provide a doorless opening of 0.15% or more of the floor area.
3 There must be a ventilator fan connected to a gas leak detector, with a ventilator capacity of 0.4 m
refrigeration ton (= compressor displacement volume / (5.7 m
using the refrigerant.
?
N O T E
Always take the maximum value between the R410A and R134a.
4 Pay special attention to the place, such as a basement, etc., where the refrigerant can stay, since refrigerant is heavier than air.
Example:
Outdoor unit (RAS-5WHVNPE)
Opening (m )
2 Fan (m
55 PMML0575 rev.2 - 03/2022
System combination
YUTAKI S / SCOMBI
YUTAKI S
YUTAKI S80
R: Total quantity of refrigerant charged (kg)
V: Room volume (m³)
C: Refrigerant concentration
Model
RAS-(4-6)WH(V)NPE
RAS-8WHNPE
RAS-10WHNPE
Model
Outdoor unit RAS-(4-6)WH(V)NPE
Indoor unit RWH-(4.0-6.0)(V)NF(W)E
Refrigerant (R410A): 3.4 kg
Floor 3.0 m
2
(RWM-5.0NE(-W))
R (kg)
Gas leak detector
/min)
3
Minimum volume (m
4HP
5/6HP
8HP
10HP
4-6HP
/h (R410A) or 14.4 m /h (R134a)) of the air conditioning system
3 3
Tonnes
2.27
3.16
4.11
R410A
2.27
-
Indoor unit
V (m³) C (kg/m )
3
3.4 7.5 0.46
)
3
7.5
7.8
11.4
12.1
7.6
/min or higher per Japanese
3
Tonnes
R134a
-
1.61
Countermeasure
1.0 m /min fan linked with gas leak
3
detector or 0.5 m opening
2