TM 9-4120-371-14
Preliminary procedure: Discharge the refrigerant system. (See para 5-6.)
Supplies: Nitrogen cylinder (item 4, Appendix E)
The refrigeration system must be purged with dry nitrogen, item 4, Appendix E, before any brazing is performed
on any component. A flow of dry nitrogen at the rate of less than 1-2 cfm (0.028-0.057 m3/minute) should be
continued during all brazing operations to minimize internal oxidation and scaling.
Nitrogen cylinders are pressurized containers. The pressure in the cylinder can exceed
2000 psi. A nitrogen pressure regulator should be used at all times when nitrogen is
used for leak check or purge operations.
Nitrogen is an inert gas. However, it also presents danger as a suffocant and,
therefore, must also be discharged in a ventilated location.
Assuming that the system has been discharged using a manifold as described in paragraph 5-6, proceed as
follows:
a. Specific component removal/repair instructions.
b. Be sure that refrigerant has been discharged. (See paragraph 5-6.)
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