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TM 9-4110-257-14
5.10
LEAK TESTING THE REFRIGERANT SYSTEM
This task covers:
Testing
INITIAL SETUP
Tools:
Refrigeration Unit Service Tool Kit
4, Section III, Appendix B
Nitrogen Regulator
6, Section III, Appendix B
Materials/Parts:
Refrigerant R-134a
12, Appendix E
Nitrogen
11, Appendix E
Equipment Conditions:
Service manifold installed (para. 5-6).
General Safety Instructions:
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.
Testing.
NOTE
•
To perform leak test, it is necessary that the system be pressurized
with a proportion of refrigerant gas.
•
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, "Leak Detector, Refrigerant Gas".
(1) 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.
(d) Open refrigerant cylinder valve and pressurize system to 100 psi (7.1 kg/cm²).
5-18
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