TM 9-4120-398-14
5-8. LEAK TESTING THE REFRIGERANT SYSTEM (cont)
CAUTION
If the soap solution testing method is used, thoroughly rinse with fresh water after using is completed.
A residual soap film will attract and accumulate an excessive amount of dust and dirt during operation.
c. Testing procedures. To perform leak testing by use of the electronic detector, it is necessary that the system be
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/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 Paragraph 510).
(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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