Mitsubishi Electric PUHY-P1000, Service Handbook

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[8-11 Measures for Refrigerant Leakage ]
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HWE14040 GB
When the power to the outdoor/indoor unit must be turned off to repair the leak after closing the service valves specified in
the item 4, turn the power off in approximately one hour after the outdoor/indoor units stop.
1) When 30 minutes have passed after the item 4 above, the indoor unit lev turns from fully closed to slightly open to prevent the
refrigerant seal.
LEV2 open when the outdoor unit remains stopped for 15 minutes to allow for the collection of refrigerant in the outdoor unit
heat exchanger and to enable the evacuation of the outdoor unit heat exchanger.
If the power is turned of in less than 5 minutes, LEV2 may close, trapping high-pressure refrigerant in the outdoor unit heat
exchanger and creating a highly dangerous situation.
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. Leak spot: In the case of extension pipe for indoor unit or optional 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 SW4 (769) 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 SW4 (769) 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 and optional unit. Do not discharge refrigerant into the at-
mosphere when it is collected.
(5) Repair the leak.
(6) After repairing the leak, perform evacuation of the extension pipe for the indoor unit and optional 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.
In the cooling cycle, the section between check valve CV1 and LEV2 will form a closed
circuit. Before recovering the refrigerant or evacuating the system, leave the unit in a stopped state for at least 15
minutes and then open LEV2 and switch SW4 (988) from OFF to ON so that LEV1 and SV5b are in an open state. If
this work is not performed, recovering the refrigerant or evacuating the system may not be possible. (After comple-
tion of work, set SW4 (988) from ON to OFF.)
2) Repair the leak.
3) After repairing the leak, perform evacuation of the entire system, and calculate the standard amount of refrigerant to be added
(for the outdoor unit, extension pipe, and indoor unit), and charge the refrigerant. For details, refer to the following page(s).
[6-9-3 The Amount of Refrigerant to Be Added](page 132)
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, LEV2 may close, trapping high-pressure refrigerant in the outdoor unit heat
exchanger and creating a highly dangerous situation.