Samsung AM160FNBFEB/EU Training Manual For Installation, Service page 40

6. Installation and Service Precautions 6. Installation and Service Precautions
- If you do not perform nitrogen flushing when welding
the pipes, oxide may form inside the pipes and cause
damage to parts such as the compressor and valves.
- Adjust the flow rate of the nitrogen flushing with a
pressure regulator to maintain 0.05m3/h or less.
- Before welding the pipes on the connection port, cover
the valve with a wet cloth. (to protect the parts within the
valve).