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TM 9-4120-389-14
c. Testing Procedures. To perform leak testing by use of the electronic detector, it is necessary that the
system by pressurized with a proportion of refrigerant gas. To perform leak testing by use of the soap solution
method, the system may be pressurized with dry nitrogen alone.
(1) To pressurize a system that has some refrigerant charge, for either leak testing method:
(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.
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 re-charge 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 charging manifold valves.
(e) Open the nitrogen tank valve and pressurize the system to 350 psi (24.7 kg/cm
2).
(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. 5-8).
(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.
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