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TM5-4120-387-14
(b) Connect the hoses from a charging manifold to the service valves.
NOTE
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.
Open the nitrogen tank valve and pressurize the system to 350 psi
(24.7 kg/cm2).
(f) Perform leak tests.
(g) If a leak if 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) 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 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 (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.
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