Precautions Against Refrigerant Leakage - Mitsubishi Electric MXZ-4C36NAHZ Service Manual

9

PRECAUTIONS AGAINST REFRIGERANT LEAKAGE

9-1. PRECAUTIONS AGAINST REFRIGERANT LEAKAGE
9-1-1. 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 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
(ISO 5149-1)
9-1-2. 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 pre-
charged refrigerant at ex-factory plus additional
charged amount at field installation.
(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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(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.
Ventilation apparatus
The smallest The second
room 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)
OCH573
/
O K
) and find the room with the smallest volume
3
Outdoor unit
Indoor unit
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Outdoor unit
Indoor unit
[ Maximum concentration(O/K)
Maximum concentration of R410A:0.44O/K
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.
Note:
When single refrigeration system consists of several inde-
pendent refrigeration circuit, figure out the total refrigerant
amount by each independent refrigerant circuit.
(b) There are partitions, but there are openings that allow
the effective mixing of air.
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Indoor unit
Opening
Wall
If the calculation results do not exceed the maximum con-
centration, perform the same calculations for the larger sec-
ond and third room, etc., until it has been determined that
nowhere the maximum concentration will be exceeded.
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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)