LG ARUN096BT2 Installation Manual - Page 43

ENGLISH Refrigerant piping installation Leak Test and Vacuum drying (1) Leak test Leak test should be made by pressurizing nitrogen gas to 551.1 psi. If the pressure does not drop for 24 hours, the system passes the test. If the pressure drops, check where the nitrogen leaks. For the test method, refer to the following figure. (Make a test with the service valves closed. Be also sure to pressurize liquid pipe, gas pipe and high/low pressure common pipe) The test result can be judged good if the pressure has not be reduced after leaving for about one day after completion of nitrogen gas pressurization. Slave 1 outdoor unit Close Close Master outdoor unit Close Close Nitrogen gas cylinder Close Nitrogen gas cylinder High/low pressure common pipe Liquide pipe Gas pipe High/low pressure common pipe Liquide pipe Gas pipe Close Liquid side Indoor unit Gas side Note: If the ambient temperature differs between the time when pressure is applied and when the pressure drop is checked, apply the following correction factor There is a pressure change of approximately 0.1MPa (14.5 psi) for each 1°C(33.8˚F) of temperature difference. Correction= (Temp. at the time of pressurization - Temp. at the time of check) X 0.1 For example: Temperature at the time of pressurization (3.8 MPa (551.1 psi) is 27 °C(80.6˚F) 24 hour later: 3.73 MPa (541 psi), 20°C(68˚F) In this case the pressure drop of 0.07 is because of temperature drop And hence there is no leakage in pipe occurred. Caution: To prevent the nitrogen from entering the refrigeration system in the liquid state, the top of the cylinder must be at higher position than the bottom when you pressurize the system. Usually the cylinder is used in a vertical standing position. Installation Manual 43