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Indoor unit
The smallest
room
The second
smallest room
Outdoor unit
Ventilation apparatus
Indoor unit
Opening
Wall
Outdoor unit
(Situation in which there
are no door openings or
in which there are open-
ings above and blow
doors that occupy at
least 0.15% of the floor
area)
Indoor unit
Outdoor unit
11-2. PRECAUTIONS AGAINST REFRIGERANT LEAKAGE
11-2-1. Introduction
R410A refrigerant of this air conditioner is non-toxic and non-
flammable but leaking of large amount from an indoor unit
into the room where the unit is installed may be deleterious.
To prevent possible injury, the rooms should be large
enough to keep the R410A concentration specified by
KHK : (a high pressure gas safety association) installation
guidelines S0010 as follows.
Note:
When a single refrigeration system consists of several
independent refrigeration circuit, figure out the total refriger-
ant amount by adding each independent refrigerant circuit.
(2) Calculate room volumes (K[ft
3
]) and find the room
with the smallest volume
The part with represents the room with the smallest
volume.
(a) Situation in which there are no partitions
(3) Use the results of calculations (1) and (2) to
calculate the refrigerant concentration:
If the calculation results do not exceed the maximum concen-
tration, perform the same calculations for the larger second and
third room, etc., until it has been determined that nowhere will
the maximum concentration be exceeded.
Indoor unit
All refrigerant of this system will leak out to this
room if there is leakage at this indoor unit.
Direction
of refrigerant flow
Outdoor unit
* Maximum concentration
Maximum refrigerant concentration of R410A of a room is
0.30 kg/K accordance with the installation guidelines.
To facilitate calculation, the maximum concentration is
expressed in units of O/K ( kg of R410A per K)
(KHK installation guidelines S0010)
Maximum concentration of R410A: 0.3O/K[0.019lbs/ft
3
]
11-2-2. Confirming procedure of R410A concentration
Follow (1) to (3) to confirm the R410A concentration and take
appropriate treatment, if necessary.
(1) Calculate total refrigerant amount by each refrig-
erant system.
Total refrigerant amount is precharged refriger-
ant amount at ex-factory plus additional charged
amount at field installation.
(b) There are partitions, but there are openings that allow
the effective mixing of air.
(c) If the smallest room has mechanical ventilation
apparatus that is linked to a household gas detection
and alarm device, the calculations should be performed
for the second smallest room.
Total refrigerant in the refrigerating unit (O
[lbs
])
[ maximum concentration
The smallest room in which an indoor (O/K
[lbs/ft
3
])
unit has been installed (K
[ft
3
])
Maximum concentration of
R410A:0.3O/K
[0.019lbs/ft
3
]
The installer and system specialist shall secure safety against leakage according to local regulations or standards.
The following standards may be applicable if local regulations are not available.