SERVICE - TM-5-4120-393-140231

TM 5-4120-393-14

5-12. Leak Testing Refrigerant System (cont)

Soap solutions. In this method, a strong solution of a liquid detergent and water is brushed onto al 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 complete. A residual soap film will attract and accumulate an excessive

amount of dust and dirt during operation.

Testing Procedures.

NOTE

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.

To pressurize a system that has some refrigerant charge, for either leak testing method.

(1) Remove the hose connection protective caps from the high and low pressure service valves.

(2) 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 the test is completed.

(3) Connect a nitrogen pressure regulator and nitrogen bottle to the center hose connection of the c arging

manifold.

(4) Open the unit service valves and the charging manifold valves.

(5) Open the nitrogen tank valve and pressurize the system to 350 psi (24.7 kg/cm ).

(6) Perform leak tests.

(7) If a leak is found, discharge and repair the system and repair leak. See specific instructions for components

to be removed.

(8) If a leak was not found and refrigerant-22 was used to pressurize the system, see charging instructions, para

To pressurize a system that has been discharged and purged for leak testing with an electronic detector.

(1) Remove the hose connection protective caps from the high and low pressure service valves.

(2) Connect the hoses from a charging manifold to the service valves.

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