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4.3 Remove foreign materials in the pipeline.
1)
The foreign materials, which enter the refrigerant pipe during installation, shall be cleaned with high pressure nitrogen.
2)
Don't connect with the indoor unit upon cleaning.
3)
Use the nitrogen instead of refrigerant or flammable toxic gases like oxygen.
4.4 Air tightness test
1)
After the refrigerant pipe is installed and connected to the indoor unit, and before the connecting pipes between the indoor and outdoor units are
connected to the valves of the outdoor units, refill the nitrogen with the pressure of 40kgf/cm² (4.0MPa) from the gas side and the fluid side
simultaneously, mark the pressure value, and then perform 24-hour air tightness test.
2)
If the pressure drops, recheck the leakage of all interfaces and then maintain the pressure for 24 hours.
3)
Don't connect with the outdoor unit during maintaining the pressure.
