TM 9-4120-388-14
5-10. LEAK TESTING THE REFRIGERANT SYSTEM - Continued.
(2) To pressurize a system that has been discharged and purged for leak testing with an electronic detector:
(a) Remove the hose connection protective caps from the high and low pressure service valves.
(b) Connect the hoses from a charging manifold to the service valves.
(c) Connect a drum of refrigerant-22 (item 8, Appendix E) to the center hose connection of the charging
manifold.
Connect the refrigerant-22 drum so that only gas will be used for pressurization.
(d) Open both unit service valves and the charging manifold valves.
(e) Open the refrigerant drum valve slightly and adjust as necessary to prevent formation of frost, and
allow system pressure to build up until the gages read 40-50 psi (28 -35 kg/mm2).
(f) Close the charging manifold valves and the refrigerant drum valve.
(g) Remove the refrigerant-22 drum from the center hose connection.
(h) Connect a nitrogen regulator and cylinder of dry nitrogen to the center hose connection.
(i) Open the charging mainifold valves and the nitrogen cylinder and regulator valve. Allow system pres-
sure to build up until gages read 350 psi (247 kg/mm2).
(j) Perform leak tests, then discharge and purge the system, in accordance with paragraphs 5-7 and 5-8
before performing maintenance, or before evacuating and charging the system, as appropriate.
(3) Final leak testing. Always perform a final leak test after performing any repair or replacement of compo-
nents before the air conditioner is reassembled and the refrigeration system is evacuated and charged.
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