Mitsubishi Electric PUHY-RP200 Service Handbook page 254

[ IX Troubleshooting ]
2) Therefore, if the power source is turned off within 30 minutes, the lev remains fully closed and the refrigerant remains sealed.
When only the power for the indoor unit is turned off, the indoor unit LEV turns from faintly open to fully closed.
3) In the cooling cycle, the section between "21S4b, c" and "LEV 2a, b" will form a closed circuit.
To recover the refrigerant or evacuate the system, "LEV1" and "SV5b, c" will be open by setting SW5-8 to ON in the stop
mode.
Set SW5-8 to OFF upon completion of all work.
3. Leak spot: In the case of extension pipe for indoor unit (Heating season)
(1) Run all the indoor units in heating test run mode.
1) To run the indoor unit in test run mode, turn SW3-2 from ON to OFF when SW3-1 on the outdoor control board is ON.
2) Change the setting of the remote controller for all the indoor units to the heating mode.
3) Check that all the indoor units are performing a heating operation.
(2) Stop all the indoor units, and stop the compressor.
1) To stop all the indoor units and the compressors, turn SW3-2 from ON to OFF when SW3-1 on the outdoor control board is ON.
2) Check that all the indoor units are stopped.
(3) Close the service valves (BV1 and BV2).
(4) Collect the refrigerant that remains inside the indoor unit. Do not discharge refrigerant into air into the atmosphere
when it is collected.
(5) Repair the leak.
(6) After repairing the leak, perform evacuation of the extension pipe for the indoor unit, and open the service valves
(BV1 and BV2) to adjust refrigerant.
4. Leak spot: In the case of outdoor unit (Heating season)
1) Collect the refrigerant in the entire system (outdoor unit, extended pipe and indoor unit).Do not discharge refrigerant into the
atmosphere when it is collected.
2) Repair the leak.
3) Repair the leak, and evacuate the air from the entire system.
(outdoor unit + extension pipe + indoor unit), and charge the system with that amount. Refer to Refer to "VIII [4] 3. " for how
to calculate the amount of refrigerant to be added.
If the indoor or outdoor units need to be turned off for repairing leaks during Step 1) above, turn off the power approximately
1 hour after the units came to a stop.
If the power is turned off in less than 15 minutes, LEV2a and LEV2b may close, trapping high-pressure refrigerant in the out-
door unit heat exchanger and creating a highly dangerous situation.
∗1 Refer to Chapter I [7] Vacuum Drying (Evacuation) for detailed procedure.
HWE10130
*1
Then, calculate the proper amount of refrigerant to be added
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