Mitsubishi Electric PURY-HP144, Service Handbook

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[8-12 Measures for Refrigerant Leakage ]
HWE18220_GB chapter 8 -
63
8 Troubleshooting Based on Observed Symptoms
8-12 Measures for Refrigerant Leakage
1. Leak spot: In the case of extension pipe for indoor unit (Cooling season)
1) Mount a pressure gauge on the service check joint (CJ2) on the low-pressure side.
2) Connect the service port on the high-pressure gas service valve (BV2) to that on the low-pressure gas service valve (BV1)
using a charge hose.
3) Stop all the indoor units. While the compressor is being stopped, turn the high-pressure gas service valve (BV2) on the outdoor
unit 45 degrees in the close direction as shown below, and fully open the low-pressure gas service valve (BV1). (Do not close
BV2 completely. Closing BV2 will cause the unit to stop in step 4.)
*Pump down operation can be performed with BV1 and BV2 open. It will take less to collect refrigerant when BV2 is closed
45 degrees.
4) Stop all the indoor units; turn on SW4 (912) on the outdoor unit control board while the compressor is being stopped. (Pump
down mode will start, and all the indoor units will run in cooling test run mode.)
5) In the pump down mode (SW4 (912)), all the indoor units and compressors will automatically stop when the low pressure
(63LS) reaches 0.383MPa [55psi] or less or 15 minutes have passed after the pump mode started. Stop all the indoor units
and compressors when the pressure indicated by the pressure gauge, which is on the check joint (CJ2) for low-pressure ser-
vice, reaches 0.383MPa [55psi] or 20 minutes pass after the pump down operation is started.
6) Close the service ball valve (BV1) on the low-pressure pipe and the service ball valve (BV2) on the high-pressure pipe on the
outdoor unit.
7) Collect the refrigerant that remains in the extended pipe for the indoor unit. Do not discharge refrigerant into the atmosphere
when it is collected.
8) Repair the leak.
9) After repairing the leak, vacuum
*1
the extension pipe and the indoor unit.
10) To adjust refrigerant amount, open the ball valves (BV1 and BV2) inside the outdoor unit, and turn off SW4 (912).
2. Leak spot: In the case of outdoor unit (Cooling season)
(1) Run all the indoor units in the cooling test run mode.
1) To run the indoor unit in test run mode, turn SW4 (769) on the outdoor unit control board to 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 SC16 value.
(This value can be displayed on the LED by setting the self-diagnosis switch SW4 (SW6-10:
OFF) on the outdoor unit control board.)
1) When SC16 is 10°C [18°F] or above: Go to the next item (3).
2) When the SC16 value is below 10°C [18°F]: After the compressor has stopped, extract the refrigerant in the system, repair
the leak, evacuate the air from the system
*1
, and charge the system with refrigerant. (If the leak is in the outdoor unit, follow
the same procedure as listed under "heating season.")
(3) Stop all the indoor units, and stop the compressor.
1) To stop all the indoor units and the compressors, turn SW4 (769) on the outdoor control board from ON to OFF.
2) Check that all the indoor units are being stopped.
*1. For details, refer to the following page(s). [1-3-3 Vacuum Drying]
SC16 self-diagnosis switch
45°
ON
1 2 3 4 5 6 7 8 9 10
ON
1 2 3 4 5 6 7 8 9 10
The figure at left shows that the switches 1 through 5 are set to ON and 6 through 10 are set to OFF.