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TM5-4120-387-14
NOTE
In accordance with Environmental Protection Agency regulations refrigerants can-
not be discharged into the atmosphere. A refrigerant recovery & recycling unit must
be used whenever discharging the refrigerant system.
Operation of the recovery/recycling unit must be by AUTHORIZED PERSONNEL
ONLY
f. Connect and operate a recovery/recycling unit in accordance with the manufacturer’s instructions.
5-7. PURGING THE REFRIGERANT SYSTEM
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 is an inert gas. However, it also presents danger as a suffocant and,
therefore, must also be discharged in a ventilated location,
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.
Change 4
5-9
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