26
4-4. Precautions during the installation of refrigerant piping
1) Precautions against refrigerant leakage
�
The limit concentration is the threshold that the emergency procedures can be performed without affecting the
human body when refrigerant has leaked into the air.
Limit concentration: 0.019 Ibs/ft
3
(0.3 kg/m
3
)
�
At the time of shipping, the outdoor unit has already been charged with the refrigerant shown below. To calcu-
late the total amount of refrigerant, add the amount of refrigerant charged at the installation site to the amount
charged at factory.
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A reference for the minimum room vol-
ume and floor area in relation to the
refrigerant amount is shown in the right
graph. If the calculated concentration
exceeds the limit concentration, be sure
to take either of the following counter-
measures.
Countermeasure1:
Provide an opening whose area is
0.15 % or more of the floor area at the
bottom of each door. Or, provide an
opening without a door.
Countermeasure2:
Provide a mechanical ventilation system
linked to a gas leakage detection
device.
Warning
�
Check that the refrigerant never exceeds the limit concentration in the room even if the
refrigerant vapor leaks inside the room.
If the refrigerant concentration in the room should exceed the limit concentration, an accident
due to lack of oxygen could occur. The refrigerant concentration is calculated as follows
If the calculated concentration exceeds the limit concentration, an opening to the next room to
make the calculated concentration lower than the limit or a mechanical ventilation system
linked to a gas leakage detector must be provided.
�
Be sure to check for refrigerant gas leakage surely.
Although the refrigerant is non-flammable, non-toxic and odorless fluorocarbon, in the event
of fluorocarbon leakage, toxic gas may be produced from contacting with fire. Moreover, since
the specific gravity of fluorocarbon is heavier than that of air, it could cover floor surface and
cause lack of oxygen.
Outdoor unit
Refrigerant type
Charged amount of refrigerant
(at the time of shipping) lbs (kg)
25.4Ibs (11.5 kg)
A
0
1
4
R
15 ton
Total amount of refrigerant in
the refrigerant equipment (lbs)
Minimum indoor volume of the room in
which the indoor unit is installed (ft
3
)
Limit concentration (Ibs/ft
3
)
{When the ceiling is 8.9 ft (2.7 m)}
ft
2
- Minimum indoor floor area
ft
3
- Minimum indoor
vo
lume
11
476.7
953.5
1430
1907
2384
2860
3337
3814
4291
4767
22 33 44 55 66 77 88
53.
82
107.
6
161.
5
215.
3
269.
1
322.
9
376.
7
430.
6
484.
4
538.
2
(If the threshold density
is within the range of
0.019 lb/ft
3
or less,
countermeasures
are not necessary.)
(If the threshold density
is within the range of
0.019 lb/ft
3
or more,
countermeasures are
necessary.)
lb. • Total refrigerant charge
