Mitsubishi Electric PUHY-200YMF-B Service Handbook page 175

[4] Location of leaks: Outdoor unit (when heating)
1 Remove any refrigerant from the entire system (outdoor unit, extension piping and indoor units).
Reclaim the refrigerant; do not discharge it into the air.
2 Repair the leaks.
3 After the leaks are repaired, replace the dryer with a new one and extract all of the air from the entire system to
create a vacuum. Then, refill with refrigerant until it reaches the calculated specification (outdoor unit + extension
piping + indoor units). Refer to "Chapter 6" for more details.
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