Refrigerant Leak - Mitsubishi Electric PUHY-P200 Service Handbook

[5] Refrigerant Leak

1. Leak spot: In the case of extended pipe for indoor unit (Cooling season)
1 Mount a pressure gauge on the check joint (CJ2) for low-pressure service.
2 Stop all the indoor units, and close the liquid ball valve (BV2) inside the outdoor unit while the compressor is
being stopped.
3 Stop all the indoor units; turn on SW3-6 on the outdoor unit main board while the compressor is being
stopped. (Pump down mode will start, and all the indoor unit will perform a test run in cooling mode.)
4 Under the pump down mode (SW3-6 is ON), the low-pressure pressure (LPS) becomes 0.382MPa or less, or all
the indoor units automatically stop in 15 minutes after the pump mode starts.
When the value of the pressure gauge, which is on the check joint (CJ2) for low-pressure service, is 0.284MPa
or when 20 minutes pass, stop all the indoor units and the compressor.
5 Close the gas ball valve (BV1) inside the outdoor unit.
6 Wipe the refrigerant that remains in the extended pipe for the indoor unit.
Do not discharge refrigerant into air into the atmosphere when it is collected.
7 Repair the leak.
8 After repairing the leak, vacuum the extended pipe for the indoor unit.
9 To adjust refrigerant, open the ball valves (BV1 and BV2) inside the outdoor unit and turn off SW3-6.
2. Leak spot: In the case of outdoor unit (Cooling season)
1 Conduct a test run for all the indoor units under the cooling mode.
(1) To start a test run for all the indoor units, turn on SW3-2 when SW3-1 on the outdoor unit main board is ON.
(2) Change the setting of the remote controller for all the indoor units to the cooling mode.
(3) Check that all the indoor units are performing a cooling operation.
2 Check the values of Tc and TH7.
(To display the values on the LED screen, use the self-diagnosis switch (SW1) on the outdoor unit main board.)
(1) When Tc-TH7 is 10K or more ···· See the next item 3.
(2) When Tc-TH7 is less than 10K ···· After the compressor stops, wipe the refrigerant inside the system, repair
[ Tc self-diagnosis switch ]
1 2 3 4 5
ON
3 Stop all the indoor units, and stop the compressor.
(1) To stop all the indoor units and the compressor, turn off SW3-2 when SW3-1 on the outdoor unit main board is ON.
(2) Check that all the indoor units are being stopped.
4 Close the ball valves (BV1 and BV2).
5 To prevent the liquid seal, extract small amount of refrigerant from the check joint of the liquid ball valve
(BV2), as the liquid seal may cause a malfunction of the unit.
6 Collect the refrigerant that remains inside the outdoor unit. Do not discharge refrigerant into air into the
atmosphere when it is collected.
7 Repair the leak.
8 After repairing the leak, replace the dryer with the new one, and perform evacuation inside the outdoor unit.
9 To adjust refrigerant, open the ball valves (BV1 and BV2) inside the outdoor unit.
Note : When the power for the outdoor/indoor unit must be turned off to repair the leak after closing the ball
valves specified in the item 4, turn the power off in approximately one hour after the
outdoor/indoor units stop.
a) If the power for the outdoor unit is turned off within 30 minutes after the item 4,
→ When the stop mode continues for 30 minutes in a row, the indoor unit LEV turns from fully closed to
faintly open to prevent the liquid seal inside the liquid pipe. Therefore, when the power for the indoor
unit is turned off within 30 minutes after the outdoor unit stops, liquid will be sealed.
b) Even if the outdoor unit LEV turns from fully closed to faintly open within 30 minutes after the outdoor
unit stops, do not turn off the power for indoor/outdoor unit until the refrigerant inside the liquid pipe
discharges into the indoor unit and into the gas pipe.
→ When only the power for the indoor unit is turned off, the indoor unit LEV turns from faintly open to
fully closed.
the leak, perform evacuation, and recharge new refrigerant.
(Leak spot: In the case of outdoor unit, handle in the same way as heating
season.)
6 7 8 9 10
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[ TH7 self-diagnosis switch ]
1 2 3 4 5 6 7 8 9 10
ON