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11. C
HARGING REFRIGERANT
The outdoor unit is factory charged, but depending on the length of
the piping when installed, the outdoor unit may require additional
charging.
For charging the additional refrigerant follow the procedure as
described in this chapter.
Refrigerant cannot be charged until all field wiring and field
piping has been completed.
Refrigerant may only be charged after performing the leak
test and the vacuum drying.
The refrigerant charge of the system must be less than
100 kg. This means that in case the calculated refrigerant
charge is equal to or more than 95 kg you must divide your
multiple outdoor system into smaller independent systems,
each containing less than 95 kg refrigerant charge.
For factory charge, refer to the unit name plate.
11.1. Precautions when adding R410A
Be sure to charge the specified amount of refrigerant in liquid state to
the liquid pipe.
Since this refrigerant is a mixed refrigerant, adding it in gas form may
cause the refrigerant composition to change, preventing normal
operation.
Before charging, check whether the refrigerant cylinder is
equipped with a siphon tube or not.
Charge the liquid
refrigerant with the
cylinder in upright
position.
Be sure to use tools exclusively for R410A to ensure required
pressure resistance and to prevent foreign materials from mixing
into the system.
Charging with an unsuitable substance may cause
explosions and accidents, so always make sure that the
appropriate refrigerant (R410A) is charged.
Refrigerant containers must be opened slowly.
11.2. Stop valve operation procedure
Do not open the stop valve until all piping and
electrical
steps
installation conditions" on page 15 are completed. If
the stop valve is left open without turning on the
power, it may cause refrigerant to build up in the
compressor, leading to insulation degradation.
Always use a charge hose for service port connection.
After tightening the cap, check that no refrigerant
leaks are present.
Size of stop valve
The sizes of the stop valves connected to the system are as listed in
the table below.
Type
5
8
Liquid line stop valve
Ø9.5
Gas line stop valve
Ø15.9 Ø19.1
(a) The model U-12MX4 supports field piping of Ø12.7 on the accessory pipe
supplied with the unit.
(b) The model U-18MX4 supports field piping of Ø15.9 on the accessory pipe
supplied with the unit.
(c) The model U-10MX4 supports field piping of Ø22.2 on the accessory pipe
supplied with the unit.
The model U-12~18MX4 supports field piping of Ø28.6 on the accessory pipe
supplied with the unit.
U-5~18MX4XPQ
Urban Multi air conditioner
4PW28163-1
Charge the liquid
refrigerant with the
cylinder in up-side-down
position.
of
"10. Checking
of
unit
and
10
12
14
16
18
(a)
(b)
Ø12.7
(c)
Ø25.4
Opening stop valve (See figure 14)
1
Service port
2
Cap
3
Hexagon hole
4
Shaft
5
Seal
1.
Remove the cap and turn the valve counterclockwise with the
hexagon wrench.
2.
Turn it until the shaft stops.
Do not apply excessive force to the stop valve. Doing
so may break the valve body, as the valve is not a
backseat type. Always use the special tool.
3.
Make sure to tighten the cap securely. Refer to the table below
Tightening torque N•m (Turn clockwise to close)
Shaft
Hexagonal
Stop valve size
Valve body
wrench
Ø9.5
5.4~6.6
Ø12.7
8.1~9.9
Ø15.9
13.5~16.5
Ø22.2
27.0~33.0
Ø25.4
Closing stop valve (See figure 14)
1.
Remove the cap and turn the valve clockwise with the hexagon
wrench.
2.
Securely tighten the valve until the shaft contacts the main body
seal.
3.
Make sure to tighten the cap securely.
For the tightening torque, refer to the table above.
11.3. How to check how many units are connected
It is possible to find out how many indoor units are active and
connected by operating the push-button switch on the printed circuit
board (A1P) of the working outdoor unit. In a multiple outdoor unit
system, you can find out how many outdoor units are connected to
the system by using the same procedure.
Make sure that all the indoor units connected to the outdoor unit are
active.
Follow the 5-step procedure as explained below.
The LEDs on the A1P shows the operating status of the outdoor
unit and the number of indoor units that are active.
x
w
OFF
The number of units that are active can be read from the LED
display in the "Monitor Mode" procedure below.
Example: in the following procedure there are 22 units active:
NOTE
Wherever during this procedure, press the
button if something becomes unclear.
BS1 MODE
You will return to setting mode 1 (H1P=
1
Setting mode 1 (default system status)
Default status (normal)
Press the
button to switch from setting mode 1 to monitor
BS1 MODE
mode.
Cap (valve lid)
Service port
13.5~16.5
4 mm
18.0~22.0
6 mm
23.0~27.0
11.5~13.9
8 mm
22.5~27.5
c
ON
Blinking
x
"OFF").
H1P H2P H3P H4P H5P H6P H7P
x x w x x x x
Installation manual
16
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