Mitsubishi Electric PUMY-P200YKM2 Technical & Service Manual page 127

10-2. PRECAUTIONS AGAINST REFRIGERANT LEAKAGE
10-2-1. Introduction
R410A refrigerant of this air conditioner is non-toxic and non-flam-
mable 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 ISO 5149-1 as follows.
Maximum concentration
Maximum refrigerant concentration of R410A of a room is
0.44kg/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
10-2-2. 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 refrigerant system
Total refrigerant amount is precharged refrigerant at ex-factory plus additional charged amount at field installation.
Note:
When the air conditioning system consists of several independent refrigerant system, figure out the total refrigerant amount
by each independent refrigerant system.
(2) Calculate room volumes (m
The part with represents the room with the smallest volume.
(a) Situation in which there are no partitions
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Indoor unit
(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.
(3) Use the results of calculations (1) and (2) to calculate the refrigerant concentration:
Total refrigerant in the refrigerating unit (O)
The smallest room in which an indoor
unit has been installed (K)
If the calculation results do not exceed the maximum concentration, perform the same calculations for the larger second
and third room, etc., until it has been determined that nowhere the maximum concentration will be exceed.
OCH675D
O
(ISO 5149-1)
) and find the room with the smallest volume
3
Outdoor unit
[ Maximum concentration(O/K)
Maximum concentration of R410A:0.44O/K
Outdoor unit
Indoor unit
/ K
(b) There are partitions, but there are openings that allow
the effective mixing of air.
Indoor unit
Ventilation apparatus
The smallest
room
127
Direction
of refrigerant flow
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All refrigerant of this system will leak out to this
room if there is leakage at this indoor unit.
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Outdoor unit
(Situation in which there
are no door openings or
in which there are open-
Opening
ings above and below
doors that occupy at
Wall
least 0.15% of the floor
area)
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Outdoor unit
Indoor unit
The second
smallest room