ARMY TM 9-4120-380-14
AIR FORCE TO 35E9-136-21
5.13. LEAK TESTING REFRIGERANT SYSTEM-Continued
SERVICE - continued
The entire repaired area should be thoroughly leek tested after repair or replacement of
any component before it is recharged with refrigerant-22. Leak testing is also the
method for troubleshooting when a system has lost all or part of its refrigerant charge
through an undetermined cause.
a. Open compound and pressure gauges on service manifold If system pressure is 50 psig or higher, proceed to
Step 1, if not, continue with Step b.
b. Open CV and PGV end allow refrigerant to enter system until compound and pressure gauges indicate a
minimum pressure of 50 psig then close CV.
Close R-22 refrigerant cylinder valve and remove yellow manifold hose.
d. Install nitrogen cylinder (paragraph 5 11).
e. Open nitrogen cylinder valve and adjust regulator to a pressure 10 psi greater than system pressure.
Loosen 1/4-inch (0.64 cm) yellow hose at charge port and purge for 3-5 seconds, then tighten.
g. Open charge valve and adjust nitrogen regulator to slowly raise compound and pressure gauge reading to 300
h. Using a halon leak detector, check all fittings, connections and components in surrounding area for leaks Insure
pressure remains at 300 psig, add more nitrogen if necessary.
Close CV and nitrogen cylinder valve. Remove yellow hose from nitrogen regulator and connect to service
manifold hose rack.
Always perform a final leak test before the air conditioner is reassembled and the refrigeration system is
evacuated and charged.