Hitachi RAS-4-HNCE - Setting the DIP Switches for the Outdoor Unit

3. Piping work and refrigerant charge
78
SMGB0079 rev.0 - 01/2013
3.5 Caution in case of refrigerant leakage
The installers and those responsible for drafting the specications are obliged to comply with local safety codes and regu-
lations in the case of refrigerant leakage.
3.5.1 Maximum permitted concentration of hydrouorocarbon (HFC)
The refrigerant R410A, charged in the UTOPIA series system, is an incombustible and non-toxic gas. However, if leakage
occurs and gas lls a room, it may cause suffocation.The maximum permissible concentration of HFC gas, R410A in air
is 0.44 kg/m
3
, according to EN378-1.
Therefore, some effective measure must be taken to lower the R410A concentration in air below 0.44 kg/m
3
to prevent
suffocation in case of leakage.
3.5.2 Calculation of refrigerant concentration
1 Calculate the total quantity of refrigerant R (kg) charged in the system by connecting all the indoor units in the rooms
to be air-conditioned.
2 Calculate the room volume V (m
3
) of each room.
3 Calculate the refrigerant concentration C (kg/m
3
) of the room according to the following equation:
C=R/V
R: Total quantity of refrigerant charged (kg).
V: Room volume (m
3
).
C: Refrigerant concentration (≤ 0.44 kg/m
3
for R410A).
3.5.3 Countermeasure for 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 size to the oor area.
3 There must be a ventilator fan connected to a gas leak detector, with a ventilator capacity of 0.4 m³/min or higher per
Japanese refrigeration ton (= compressor displacement volume / 5.7 m³/h) of the air conditioning system using the
refrigerant.
IVX Premium series
Model Tonnes
RAS-2HVNP
0.88
RAS-2.5HVNP
1.14
RAS-3HVNPE
1.17
RAS-(4-6)H(V)NPE
2.27
RAS-8HNPE
3.16
RAS-10HNPE / RAS-12HNP
4.11
IVX Standard series
Model Tonnes
RAS-3HVNC
1.35
RAS-4H(V)NCE
1.64
RAS-(5/6)H(V)NCE
2.27
RAS-8HNCE
3.16
RAS-10HNCE / RAS-12HNC
4.11
4 Pay a special attention to the place, such as a basement, etc., where refrigerant can stay, since refrigerant is heavier
than air.