TM 9-4120-398-14
This task cover:
Service
INITIAL SETUP
Tools
Equipment Condition
Power OFF
Tool kit, refrigeration SVC
Condenser access door open
Conducted after repair involving
opening of the refrigerant system
Materials/Parts
General Safty Instructions
WARNING
Nitrogen cylinder
(Item 9 Appendix E)
Refrigerant -22
Voltages used can kill. Always
(Item 8 Appendix E)
disconnect power cord to air conditioner
before performing any internal
maintenance. Shutting unit off at its
control panel does not disconnect
unit power.
Service.
a. The entire repaired area should be thoroughly leak 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.
b. Testing Method. There are two acceptable methods for leak testing the refrigeration system.
(1) Refrigerant gas leak detector. If an electronic refrigerant gas leak detector is available, it should be used in
accordance with the procedures contained in TM 9-4940-43514, "Leak Detector, Refrigerant Gas."
NOTE
The electronic refrigerant gas leak detector is highly sensitive to the presence of a minute quantity of gas
in the air, and due to this factor is quite effective in the detection of small leaks. However, due to the rapid
dispersion of refrigerant gas into the surrounding air, difficulty may be encountered in pinpointing large leaks.
The detector must be used in a well ventilated but draft free area.
(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.