Mitsubishi Electric CITY MULTI PQRY-P250 Installationshandbuch Seite 15

2 Evacuation
As shown in the figure below, evacuate with the ball valve of the heat source unit closed and evacuate both the connection piping and the indoor unit
from the service port provided on the ball valve of the heat source unit using a vacuum pump. (Always evacuate from the service port of both the
liquid pipe and the gas pipe.) After the vacuum reaches 5 Torr, continue evacuation for at least one hour or more. Then, stop the vacuum pump and
let stand for one day and check if the vacuum does not rise. (If the vacuum increases by 1 Torr, since water may be mixed in, pressurize up to
0.05 MPa using dry nitrogen gas and evacuate again.) Finally, seal with liquid refrigerant from the liquid pipe. Moreover, during operation, adjust the
refrigerant amount from the gas pipe so that the refrigerant is always an appropriate amount.
* Never perform air purging using refrigerant.
A System analyzer
B Lo Knob
C Hi Knob
D Ball valve
E Liquid pipe
F Gas pipe
G Service port
H Three-way joint
I Valve
J Valve
K R407C cylinder
L Scale
Use a graviometer. (One that can measure down to 0.1 kg.)
M Vacuum pump
Use a vacuum pump with a reverse flow check valve.
(Recommended vacuum gauge: ROBINAIR 14010 Thermistor Vacuum Gauge)
Also use a vacuum pump that reaches 0.5 Torr or greater after operating for five minutes.
Note:
• Always add an appropriate amount of refrigerant. (For the refrigerant additional charge, see pages 11 .) Also always seal the system with
liquid refrigerant. Too much or too little refrigerant will cause trouble.
• Use a gauge manifold, charging hose, and other parts for the refrigerant indicated on the unit.
3 Refrigerant Charging
Since the refrigerant used with the unit is nonazerotropic, it must be charged in the liquid state. Consequently, when charging the unit with refrigerant
from a cylinder, if the cylinder does not have a syphon pipe, charge the liquid refrigerant by turning the cylinder upside-down as shown below. If the
cylinder has a syphon valve like that shown in the figure at the right, the liquid refrigerant can be charged with the cylinder standing upright.
Therefore, give careful attention to the cylinder specifications. If the unit should be charged with gas refrigerant, replace all the refrigerant with new
refrigerant. Do not use the refrigerant remaining in the cylinder.
A
A R407C cylinder
B Syphon pipe
C Liquid refrigerant
LO
B
[When cylinder does not have a syphon pipe]
D
E
F
A
HI
C
G
H
K
A
I
M
J
L
[When cylinder has a syphon pipe
(Refrigerant can be charged with the
cylinder standing upright.)]
B
C
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