Preparation, Repairs And Refrigerant Refilling When Repairing Leaks; Location Of Leaks: Extension Piping Or Indoor Units (When Cooling); Location Of Leaks: Heat Source Unit (Cooling Mode) - Mitsubishi Electric CITY MULTI PQRY-P200YMF-B Service Handbook

8 8 8 8 8 PREPARATION, REPAIRS AND REFRIGERANT REFILLING WHEN REPAIRING
LEAKS

[1] Location of leaks: Extension piping or indoor units (when cooling)

1 Attach a pressure gage to the low-pressure servicing check joint (CJ2).
2 Stop all of the indoor units. When the compressor has stopped, shut off the liquid ball valve (BV2) for the heat
source unit.
3 Stop all of the indoor units. When the compressor has stopped, turn the SW3-6 switch on the main board for the
heat source unit to ON. (This will start the pump down operation causing all of the indoor units to enter the
cooling mode.)
4 While in the pump down operation (SW3-6 ON), the low pressure (LPS) will reach below at least 2 kg/cm
(0.20 MPa) or the indoor unit and the compressor will automatically shut down within 15 minutes of starting the
pump down operation. Shut down all of the indoor units and the compressor if the pressure gage for the low-
pressure servicing joint (CJ2) reads 1.5 kg/cm
minutes.
5 Shut off the gas ball valve (BV1) for the heat source unit.
6 Remove any refrigerant remaining in the extension piping and the indoor units.
Be sure to recover the refrigerant without releasing it into the air.
7 Repair the location of the leak.
8 After repairing the leak, create a vacuum to remove any air from inside of the extension piping or the indoor
units.
9 Open the ball valves for the heat source unit (BV1 and BV2), turn the SW3-6 switch to OFF, adjust refrigerant
levels and confirm proper circulation.

[2] Location of leaks: Heat Source Unit (Cooling mode)

1 Test run all indoor units in cooling mode.
1. With SW3-1 on the MAIN board of the heat source unit set to ON and SW3-2 OFF → ON to test run all
indoor units.
2. Change the remote controller settings so that all indoor units run in cooling mode.
3. Check that all indoor units are running in cooling mode.
2 Check the Tc and SC16 data.
(The LED monitor switch (SW1) on the MAIN board of the heat source unit can be used to display this data on
the LED.)
1. If SC16 is 10 degrees or more ................. Continue to step 3.
2. If SC16 is less than 10 degrees ............... After stopping the compressor, remove any refrigerant, repair the
[Tc LED monitor switch]
1 2 3 4 5 6 7 8 9 10
ON
3 Stop all indoor units and the compressor.
1. With SW3-1 on the MAIN board of the heat source unit set to ON and SW3-2 ON → OFF to stop all indoor units
and the compressor.
2. Check that all indoor units have been stopped.
4 Close both ball valves (BV1 and BV2).
5 Remove a small amount of refrigerant from the liquid ball valve (BV2) check joint. If this operation is not performed,
remaining refrigerant may cause the unit to malfunction.
6 Remove any refrigerant remaining in the heat source unit.
Reclaim the refrigerant; do not discharge it into the air.
7 Repair the leak point.
8 After the leak point is repaired, change the dryer and extract all of the air from the heat source unit to create a
vacuum.
9 Open both ball valves (BV1 and BV2) on the heat source unit, then adjust the refrigerant amount and verify that the
refrigerant is circulating properly.
2
G (0.15 MPa) or after running the pump down operation for 20
leak point, then extract the air to create a vacuum and refill with
new refrigerant (same procedure as 4. Location of leaks: Heat
source unit (when heating)).
[SC16 LED monitor switch]
1 2 3 4 5 6 7 8 9 10
ON
–141–
2
G