User Guide

WARNINGS ON REFRIGERANT LEAKAGE
For the amount of charge in this example:
The possible amount of leaked refrigerant gas in
rooms A, B and C is 10kg.
The possible amount of leaked refrigerant gas in
rooms D, E and F is 15kg.
NOTE 2 :
The standards for minimum room volume are as follows.
(1) No partition (shaded portion)
(2) When there is an effective opening with the adjacent
room for ventilation of leaking refrigerant gas
(opening without a door, or an opening 0.15% or
larger than the respective floor spaces at the top or
bottom of the door).
(3) If an indoor unit is installed in each partitioned room
and the refrigerant piping is interconnected, the
smallest room of course becomes the object. But
when a mechanical ventilation is installed interlocked
with a gas leakage detector in the smallest room
where the density limit is exceeded, the volume of
the next smallest room becomes the object.
NOTE 3 :
The minimum indoor floor area compared with the
amount of refrigerant is roughly as follows:
(When the ceiling is 2.7m high)
Check of Concentration Limit
The room in which the air conditioner is to be
installed requires a design that in the event of
refrigerant gas leaking out, its concentration will not
exceed a set limit.
The refrigerant R410A which is used in the air
conditioner is safe, without the toxicity or combustibility of
ammonia, and is not restricted by laws to be imposed
which protect the ozone layer. However, since it contains
more than air, it poses the risk of suffocation if its
concentration should rise excessively. Suffocation from
leakage of R410A is almost non-existent. With the recent
increase in the number of high concentration buildings,
however, the installation of multi air conditioner systems
is on the increase because of the need for effective use
of floor space, individual control, energy conservation by
curtailing heat and carrying power etc.
Most importantly, the multi air conditioner system is able
to replenish a large amount of refrigerant compared with
conventional individual air conditioners. If a single unit of
the multi conditioner system is to be installed in a small
room, select a suitable model and installation procedure
so that if the refrigerant accidentally leaks out, its
concentration does not reach the limit (and in the event
of an emergency, measures can be made before injury
can occur).
In a room where the concentration may exceed the limit,
create an opening with adjacent rooms, or install
mechanical ventilation combined with a gas leak
detection device.
The concentration is as given below.
Total amount of refrigerant (kg)
Min. volume of the indoor unit installed room (m³)
≤ Concentration limit (kg/m³)
The concentration limit of R410A which is used in multi
air conditioners is 0.3kg/m³.
NOTE 1 :
If there are 2 or more refrigerating systems in a single
refrigerating device, the amounts of refrigerant should be
as charged in each independent device.
Important
Outdoor unit
e.g.,
charged amount (15kg)
e.g., charged
amount (10kg)
Indoor unit
Room A Room B Room C Room D Room E Room F
Outdoor unit
Refrigerant piping
Indoor unit
Outdoor unit
Refrigerant piping
Indoor unit
Very
small
room
Small
room
Medium
room
Large room
Mechanical ventilation device - Gas leak detector
0
5
10
10 20 30
15
20
25
30
35
40
Range below the
density limit
of 0.3 kg/m³
(countermeasures
not needed)
Range above
the density limit
of 0.3 kg/m³
(countermeasures
needed)
Total amount of refrigerant
kg
Min. indoor floor area
m²