Compressor Replacement Instructions (Only P168-P234 Types) - Mitsubishi Electric CITY MULTI PUHY-P108 Service Handbook

10) To adjust refrigerant amount, open the ball valves (BV1 and BV2) inside the outdoor unit.
Note : When the power to the outdoor/indoor unit must be turned off to repair the leak after closing the ball valves
specified in the item 5, turn the power off in approximately one hour after the outdoor/indoor units stop.
(i) 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.
(ii) 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 (Heating season)
1) Run all the indoor units in heating test run mode.
(i) To run the indoor unit in test run mode, turn SW3-2 from ON to OFF when SW3-1 on the outdoor MAIN board
is ON.
(ii) Change the setting of the remote controller for all the indoor units to the heating mode.
(iii) Check that all the indoor units are performing a heating operation.
2) Stop all the indoor units, and stop the compressor.
(i) To stop all the indoor units and the compressors, turn SW3-2 from ON to OFF when SW3-1 on the outdoor MAIN
board is ON.
(ii) Check that all the indoor units are stopped.
3) Close the ball valves (BV1 and BV2).
4) Collect the refrigerant that remains inside the outdoor 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 ball 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 refriger-
ant into the atmosphere when it is collected.
2) Repair the leak.
3) After repairing the leak, replace the dryer with the new one, and perform evacuation of the entire system, and cal-
culate the standard amount of refrigerant to be added (for outdoor unit, extended pipe and indoor unit), and charge
the refrigerant.
Refer to "8 [4] 3. "

[6] Compressor Replacement Instructions (only P168-P234 types)

Follow the instructions below when replacing the compressor.
When replacing the compressor No.1 (inverter drive), determine if the compressor is malfunctioning or the inverter is malfunc-
tioning.
When only one compressor is malfunctioning, operate the compressor for approximately an hour in emergency operation mode
before the replacement, check the items below, and replace the compressor after examining whether the return oil circuit is
working properly or not.
Refer to the diagram on the right for the temperature of each section.
<When normal>
1) Temperature of A = Temperature of C,
and Temperature of A > Outdoor temperature + 10deg°C [18deg°F]
2) Temperature of B = Temperature of C,
and Temperature of B > Outdoor temperature + 10deg°C [18deg°F]
<When abnormal>
When 1) is abnormal (out of range)
Return oil failure due to SV1 circuit failure
-> Replace SV1 circuit.
When 2) is abnormal (out of range)
Return oil failure due to capillary blockage
-> Replace the capillary
Compressor
- 351 -
[ IX Troubleshooting ]
4-way valve
A
SV1 C
Oil
B
separator
Capillary