ARMY TM 9-4120-380-14
AIR FORCE TO 35E9-136-21
5.11. PURGING REFRIGERANT SYSTEM. This task covers service.
Tool kit. service, refrigeration unit (Item 1, Appendix B)
Death or serious injury may result If personnel fall to observe safety precautions Use
great care to avoid contact with liquid refrigerant or refrigerant gas being discharged
under pressure Sudden and irreversible tissue damage can result from freezing. Wear
thermal protective gloves and a face protector or goggles m any situation where skin-
eye-contact is possible.
Prevent contact of refrigerant gas with flame or hot surfaces Heat causes the refrigerant
to break down and form carbonyl chloride (phosgene), a highly poisonous and corrosive
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. Do not allow nitrogen pressure regulator setting
to exceed 200 psig during purging. Nitrogen is an inert gas However, it also presents
danger as a sufficient and. therefore, must also be discharged in a ventilated location.
The refrigeration system must be purged with dry nitrogen (Item 9, Appendix E), before
any brazing or debrazing is performed on any component. A flow of dry nitrogen at the
rate of less than 1-2 cfm (0.028-0.057 m /minute) should be continued during all brazing
or debrazing operations to minimize internal oxidation and scaling.