TM 9-4120-398-14
5-6. PURGING THE REFRIGERANT SYSTEM (cont)
d. Close the unused valve on the charging manifold, and open the one with the nitrogen tank hook up.
e. Open the nitrogen cylinder valve and adjust the regulator so that 1 to 2 cfm (0.028-0.057 m3/minute) of nitrogen
flows through the system.
f. Check discharge from hose attached to the low pressure charging valve to be sure that no oil is being forced out of the
system.
g. Allow nitrogen to sweep through the system at the rate of less than 12 cfm (0.028 0.057 m3/minute) for a minimum
of 5 minutes, before starting any brazing operation. Then allow it to continue to flow at the same rate until all brazing
operations are completed (See Paragraph 5-7 for brazing/debrazing procedures).
h. After installation brazing operations are completed, allow nitrogen to flow for a minimum of 5 minutes.
i.
Close nitrogen cylinder valve, nitrogen regulator and charging manifold valve.
Disconnect the hose from the nitrogen tank.
j.
k. Replace filter drier (see Paragraph 5-21).
l. Leak test system (see Paragraph 5-8).
