SiBE34-802 Test OperationTest Operation 751.1.3 Air Tight Test and Vacuum Drying Air tight test: Make sure to use nitrogen gas. Pressurize the liquid and gas pipes to 4.0 MPa (40 bar) (do not pressurize more than 4.0MPa (40 bar)). If the pressure does not drop within 24 hours, the system passes the test. Ifthe pressure drops, check where the nitrogen leaks from. Vacuum drying: Use a vacuum pump which can evacuate to –100.7 kPa (5 Torr, –755 mmHg)1. Evacuate the system from the liquid and gas pipes by using a vacuum pump for morethan 2 hours and bring the system to –100.7 kPa. After keeping the system under thatcondition for more than 1 hour, check if the vacuum gauge rises or not. If it rises, thesystem may either contain moisture inside or have leaks.2. Following should be executed if there is a possibility of moisture remaining inside thepipe (if piping work is carried out during the raining season or over a long period of time,rainwater may enter the pipe during work).After evacuating the system for 2 hours, pressurize the system to 0.05 MPa (vacuum break)with nitrogen gas and evacuate the system again using the vacuum pump for 1 hour to –100.7kPa (vacuum drying). If the system cannot be evacuated to –100.7 kPa within 2 hours, repeatthe operation of vacuum break and vacuum drying.Then, after leaving the system in vacuum for 1 hour, confirm that the vacuum gauge does notrise.1.1.4 Additional Refrigerant Charge Refrigerant cannot be charged until field wiring has been completed. Refrigerant may only be charged after performing the leak test and the vacuum drying (seeabove). When charging a system, care shall be taken that its maximum permissible charge is neverexceeded, in view of the danger of liquid hammer. Charging with an unsuitable substance may cause explosions and accidents, so alwaysensure that the appropriate refrigerant (R-410A) is charged. Refrigerant containers shall be opened slowly. Always use protective gloves and protect your eyes when charging refrigerant. When performing service on the unit requiring the refrigerant system to be opened,refrigerant must be evacuated according to local regulations. Do not use the automatic refrigerant charging function while working on the indoor units.When using the automatic refrigerant charging function, the indoor units operateautomatically as well as the outdoor unit. When the power is on, please close the front panel when leaving the unit.Pressure reducing valveNitrogenTank SiphonsystemMeasuringinstrumentVacuumpompValve AOutdoor unitGas line stop valveStop valve service portCharge hoseFig. 6Liquid line stop valveIndoor unitIndoor unit
