TM 9-4120-403-14
(2)
Soap solutions. In this method, a strong solution of a liquid detergent and water is brushed onto all
points of possible leakage while closely watching for the formation of bubbles.
CAUTION
If the soap solution testing method is used, thoroughly rinse with fresh water after testing is completed. A
residual soap film will attract and accumulate an excessive amount of dust and dirt during operation.
c Testing procedure. 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 ill 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 hose connection of the charging
manifold.
(d)
Open the unit service valves and the charging manifold valve.
(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 repair leak. See specific instruction 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 5-12.)
(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.
5-21
