Precautions Against Refrigerant Leakage - Mitsubishi MXZ-8B140VA Technical & Service Manual

12-3. PRECAUTIONS AGAINST REFRIGERANT LEAKAGE

12-3-1. 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 deleteri-
ous.
To prevent possible injury, the rooms should be large
enough to keep the R410A concentration specified by ISO
5149-1 as follows.
Maximum concentration
Maximum refrigerant concentration of R410A of a room
is 0.44 kg/K accordance with ISO 5149-1.
To facilitate calculation, the maximum concentration is
expressed in units of O/K ( kg of R410A per K)
Maximum concentration of R410A: 0.44
(ISO 5149-1)
Outdoor unit
Direction
of refrigerant flow
Indoor unit
All refrigerant of this system will leak out to this
room if there is leakage at this indoor unit.
12-3-2. 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 refrigerant
at ex-factory plus additional charged amount at
field installation.
Note:
When single refrigeration system consists of several inde-
pendent refrigeration circuit, figure out the total refrigerant
amount by each independent refrigerant circuit.
OCH480D
(2) Calculate room volumes (m³) and find the room
The part with represents the room with the smallest
volume.
/
O K
(b) There are partitions, but there are openings that allow
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(c) If the smallest room has mechanical ventilation appa-
(3) Use the results of calculations (1) and (2) to cal-
Total refrigerant in the refrigerating unit (O)
The smallest room in which an indoor
unit has been installed (K)
Maximum concentration of R410A: 0.44O/K
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 the maximum
concentration does not exceed in each room.
63
with the smallest volume
(a) Situation in which there are no partitions
Branch box
Indoor unit
the effective mixing of air.
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Indoor unit
Opening
Wall
ratus that is linked to a household gas detection and
alarm device, the calculations should be performed for
the second smallest room.
Ventilation apparatus
The smallest The second
room smallest room
culate the refrigerant concentration:
Outdoor unit
Outdoor unit
(situation in which there
are no door openings or
in which there are open-
ings above and below
doors that occupy at
least 0.15% of the floor
area)
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Outdoor unit
Indoor unit
[ Maximum concentration (O/K)