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TM5-4120-377-14
(b) Connect the hoses from a charging manifold to the service valves.
If it is possible that the problem may not be a leak and that you may not have to replace a
refrigeration system component, refrigerant-22 may be substituted for the nitrogen in the
following test. If nitrogen is used, you will have to discharge, evacuate, and recharge the
system after this test is completed.
(c) Connect a nitrogen pressure regulator and nitrogen bottle to the center hose connection of the
charging manifold.
(d) Open the unit service valves and the charging manifold valves.
(e) Open the nitrogen tank valve and pressurize the system to 350 psi (24.7 kg/cm2).
(f) Perform leak tests.
(g) If a leak is found, discharge and purge the system and repair leak. See specific instructions for
components to be removed.
(h) If a leak was not found and refrigerant-22 was used to pressurize the system, see charging
instructions. (See para 5-11.)
(2) To pressurize a system that has been discharged and purged for leak testing with an electronic
detector:
(a)
(b)
(c)
(d)
(e)
Remove the hose connection protective caps from the high and low pressure service valves.
Connect the hoses from a charging manifold to the service valves.
Connect a drum of refrigerant-22 to the center hose connection of the charging manifold.
Connect the refrigerant-22 drum so that only gas will be used for pressurization.
Open both unit service valves and the charging manifold valves.
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 (2.8 -3.5 kg/cm2).
(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 cyclinder of dry nitrogen to the center hose connection.
(i) Open the charging manifold valves and the nitrogen cylinder and regulator valve. Allow system
pressure to build up until gages read 350 psi (24.7 kg/cm2).
(j) Perform leak tests, then discharge and purge the system, in accordance with paragraphs 5-8 and
5-7 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
components before the air conditioner is reassembled and the refrigeration system is evacuated and charged.
5-13
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