Location Of Leaks: Outdoor Unit (Cooling Mode); Location Of Leaks: Extension Piping Or Indoor Units (Heating Mode) - Mitsubishi Electric CITY MULTI PUHY-400YMF-C Service Handbook

[2] Location of leaks: Outdoor unit (Cooling mode)

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
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 outdoor unit can be used to display this data on
the LED.)
1. If SC16 is 10 degrees or more ................. Continue to step
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 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 dryer 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.

[3] Location of leaks: Extension piping or indoor units (Heating mode)

1
Test run all indoor units in heating mode.
1. With SW3-1 on the MAIN board of the outdoor unit set to ON and SW3-2 OFF
units.
2. Change the remote controller settings so that all indoor units run in heating mode.
3. Check that all indoor units are running in heating mode.
2
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
and the compressor.
2. Check that all indoor units have been stopped.
3
Close both ball valves (BV1 and BV2).
4
Remove any refrigerant remaining in the extension piping or the indoor units.
Reclaim the refrigerant; do not discharge it into the air.
5
Repair the leaks.
6
After the leaks are repaired, extract all air from the extension piping and the indoor units to create a vacuum.
Then, open both ball valves (BV1 and BV2), then adjust the refrigerant amount and verify that the refrigerant is
circulating properly.
3
.
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)).
[SC16 LED monitor switch]
1 2 3 4 5 6 7 8 9 10
ON
-200-
ON to test run all indoor
OFF to stop all indoor units and
ON to test run all indoor
OFF to stop all indoor units