5. Electrical
Wring
◆
Turn off the main power switch of the indoor unit and the outdoor unit, then wait for more than 10 minutes
before electrical wiring work or a periodical check is performed.
◆
Ensure that the indoor fan and the outdoor fan have been stopped before electrical wiring work or a
periodical check is performed.
◆
Protect the wirings, electrical parts, and so on. from rats or other small animals. If not, rats may gnaw at
unprotected parts and which may lead to a f
i
re.
◆
Avoid the wirings touching the refrigerant pipes, plate edges and electrical parts inside the unit. If not, the
wirings will be damaged and a f
i
re may
occur
.
◆
Secure the cables. External forces on the terminals can lead to a fire.
◆
The indoor unit fan may continue to operate for up to five minutes following the heating cycle to dissipate
residual heat from the indoor unit.
29
NOTE:
R: Total Quantity of Charged Refrigerant (kg)
V: Room Volume (m
3
)
C:
Critical Concentration (0.42kg/m
3
)
* This value should be decided according to the each country’s regulation such as ISO5149,EN378 and
ASHRAE
Standard 15. In the case that the calculated critical concentration is higher than this value, take
the
following actions:
1) Provide a gas leakage detector and exhaust fan controlled by its gas leakage detector.
2) Provide effective opening in the wall or door for ventilation to next door so that the critical gas concentration
can
be maintained lower than the above value. (Provide an opening with area greater than 0.15% of the
floor surface
at the lower part of a door.)
● Special Attention Regarding Refrigerant Gas Leakage
Pay attention to the critical gas concentration to avoid accidental refrigerant gas leakage before
installing air conditioning systems.
≤
1. Maximum Permissible Concentration of HFC GAS R410A
The refrigerant R410A is an incombustible and non-toxic gas.
However, if leakage occurs and gas fills a room, it may cause suffocation.
Once leakage occurs, it is a must to take effective actions to make the concentration of R410A lower than
0.42 kg/m
3
.
Calculation of Refrigerant Concentration
(1) Calculate the total quantity of refrigerant R (kg) charged in the system connecting all the indoor units of
target
rooms.
(2) Calculate the volume of the room installing this unit
V
(m
3
).
Calculate the refrigerant concentration C (kg/m
3
) of the room according to the above equation.
Please follow local codes or regulations, if any.
2.
3.
