0 .When Refrigerant Leaks; Repairing Leaks: Preparation, Making Repairs, And Recharging The System With Refrigerant; Location Of Leaks: Extension Piping Or Indoor Unit; Location Of Leaks: Outdoor Unit - Mitsubishi CITY MULTI PUD-P250YMF-C Service Handbook

0 0 .When Refrigerant Leaks

1 1 Repairing Leaks: Preparation, making repairs, and recharging the system with
refrigerant.

[1] Location of leaks: Extension piping or indoor unit

1 Connect a pressure gauge to the low-pressure servicing check joint CJ2.
2 Test run all indoor units in cooling mode.
1. With SW3-1 on the MAIN board of the outdoor unit set to ON and SW3-2 OFF
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.
3 Perform a pump down operation.
1. Close the liquid ball valve (BV2) on the outdoor unit to begin the pump down.
4 When the pressure gauge on the low-pressure servicing check joint CJ2 reads 0.20MPa, stop all
and the compressor
1. With SW3-1 on the MAIN board of the outdoor unit set to ON and SW3-2 ON
and the compressor.
2. Check that all indoor units have been stopped.
5 Close the gas ball valve (BV1) on the outdoor unit.
6 Remove any refrigerant remaining in the extension piping or the indoor units.
Reclaim the refrigerant; do not discharge it into the air.
7 Repair the leak point.
8 After the leak point is repaired, extract all air from the extension piping and the indoor units to create a vacuum.
9 Open both ball valves (BV1 and BV2) on the outdoor unit, then adjust the refrigerant amount and verify that the
refrigerant is circulating properly.

[2] Location of leaks: Outdoor unit

1 Test run all indoor units in cooling mode.
1. With SW3-1 on the MAIN board of the outdoor unit set to ON and SW3-2 OFF
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 TH7 data
(The self-diagnosis switch (SW1) on the MAIIN board of the outdoor unit can be used to display this data on
the LED.)
1. If Tc – TH7 is 10 degrees or more ........... Continue to step 3 .
2. If Tc – TH7 is less than 10 degrees ......... After stopping the compressor, remove any refrigerant, repair the
[Tc self-diagnosis 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 outdoor unit set to ON and SW3-2 ON
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 outdoor 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 drier and extract all of the air from the outdoor unit to create a vacuum.
9 Open both ball valves (BV1 and BV2) on the outdoor unit, then adjust the refrigerant amount and verify that the
refrigerant is circulating properly.
.
leak point, then extract the air to create a vacuum and refill with
new refrigerant (same procedure as 4. Location of leaks: Outdoor
unit (when heating)).
[TH7 self-diagnosis switch]
- 127 -
ON to test run all indoor units.
OFF to stop all indoor units
ON to test run all indoor units.
1 2 3 4 5 6 7 8 9 10
ON
OFF to stop all indoor units and
indoor units