Mitsubishi SRK50ZHX-S Technical Manual page 62

7.3.2 New installation work (when using new refrigerant piping)
(1) Air purge by vacuum pump and gas leakage inspection (see Fig. 6)
a) Connect the charge hose to the outdoor unit. 1
b) Connect the charge hose to the vacuum pump adapter. 2
At this time, keep the control valves in the fully closed position. 3 4
c) Place the handle Lo in the fully opened position 5, and turn on the vacuum pump's power switch.
During this step, perform evacuating (about 10 ~ 15 minutes); for the evacuating time, refer to the equipment manufacturer's
manual.
d) When the compound gauge's pointer has indicated -0.1 MPa (-76 cmHg) 6, place the handle Lo in the fully closed position 5,
and turn OFF the vacuum pump's power switch
Keep this state for 1~2 minutes, and ascertain that the compound gauge's pointer does not return.
e) Fully open the control valves. 3 4
f) Detach the charge hoses. 1 2
g) Tightly secure the cap on the service port. 7
h) After securing the caps on the control valves, check the caps' periphery if there is any gas leakage. 3 4 7
(2) Additional refrigerant charging required for refrigerant piping length longer than standard length (The following steps should be
taken following the step e) in (1) above. See Fig. 7)
a) Set the refrigerant cylinder to the electronic balance, and connect the connecting hoses on the cylinder and electronic balance's
connecting port.
* Caution:
Be sure to make setting so that liquid can be charged. When using a cylinder equipped with a siphon, liquid can be charged
without turning it upside down.
b) Connect the gauge manifold's charge hose to the electronic balance's connecting port. 3 2
c) Open the refrigerant cylinder's valve, and, after opening the charging valve a little, close it. 1 2
d) After making zero (0) adjustment, open the charging valve and, by opening the gauge manifold's valve Lo, charge the liquid
refrigerant. 2 5
(Before handling the electronic balance, refer to its instruction manual).
e) When the designated amount of refrigerant could not be charged, make additional charging bit by bit by cooling operation (for
the amount of each addition, follow the instruction manual prepared by the equipment manufacturer). If the first additional
charging was not enough, make the second additional charging after about one minute in the same manner as the first addi-
tional charging.
* Caution:
Be sure never to charge a large amount of liquid refrigerant at once to the unit in cooling mode, since liquid is charged from
the gas side.
6 Compound pressure
gauge
-76cmHg
5 Handle Lo
1 Charge hose
3 Control valve (2-way)
7 Service port
4 Control valve
(3-way)
Fig.6 Configuration of air purge by vacuum pump
Gauge manifold
8 Handle Hi (always closed)
2 Charge hose
Vacuum pump adapter
Vacuum pump
Caution:
• Be sure to use the vacuum pump, vacuum pump adapter and
gauge manifold to refer to their instruction manuals beforehand.
• Ascertain that the vacuum pump is filled with oil to the level
designated on the oil gauge.
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