TM 9-4120-411-14
5.7 LEAK TESTING THE REFRIGERANT SYSTEM.
THIS TASK COVERS:
a. Testing
Initial Setup:
Tools
Materials/Parts
Refrigeration Unit Service Tool Kit
Refrigerant R- 134a
Nitrogen Regulator
Nitrogen
a. Testing.
WARNING
Never pressurize refrigerant lines with oxygen, mixture with oil could cause an
explosion.
The pressure in a nitrogen cylinder can exceed 2000 psi. A nitrogen pressure
regulator should be used at all times to avoid personal injury.
Nitrogen is an inert gas that can cause suffocation and must be discharged in a
well ventilated area.
NOTE
To perform leak test, it is necessary that the system be pressurized with a
The electronic gas tester is highly sensitive to the presence of a minute quantity of
gas in the air, and is quite effective in the detection of small leaks. However, due
to rapid dispersion of refrigerant gas into surrounding air, difficulty may be
encountered in pinpointing large leaks. The detector must be used in a well
ventilated area but draft free area.
Use procedures contained in
TM 9-4940-435-14&P, "Leak Detector, Refrigerant Gas".
(2) To pressurize a system that has some refrigerant charge.
(a) Connect the charge hose to a refrigerant cylinder containing refrigerant R-134a set to deliver gas
only.
(b) Check that service manifold vacuum valve is closed.
(c) Open the service manifold compound gage, pressure gage, and charge valves.
2
(d) Open refrigerant cylinder valve and pressurize system to 100 psi (7.1 kg/cm ).
(3) To pressurize a system that has had the refrigerant removed and recovered then purged.
(a) Connect the charge h se to a refrigerant cylinder containing refrigerant R-134a set to deliver gas
o
only.
(b) Check that service manifold vacuum valve is closed.
(c) Open the service manifold compound gage, pressure gage, and charge valves.
5-12.2 Change 1