TM 9-4120-370-14
TO 35E9-229-1
5-8.
PURGING THE REFRIGERANT SYSTEM - Continued.
F i g u r e 5-5. Nitrogen Purging Connection
Assuming that the system has been discharged using a manifold as described in paragraph 57, proceed as follows:
a. See specific component removal/repair instructions.
b. Be sure that refrigerant has been discharged. (See paragraph 5-7.)
c. Connect the center hose from the charging manifold to a nitrogen regulator and dry nitrogen tank.
d. The hose from the high pressure sewice valve to the charging manifold must be connected.
e. The hose from the low pressure service valve must be disconnected from the charging manifold.
f.
Open both service valves on the unit.
g. Close the unused valve on the charging manifold, and open the one with the nitrogen tank hook up.
h. Open the nitrogen cylinder valve and adjust the regulator so that less than 1-2 cfm (0.0280.057 m3/minute)
of nitrogen flows through the system.
i. Check discharge from hose attached to the low pressure charging valve to be sure that no oil is being forced
out of the system.
j. Allow nitrogen to sweep through the system at the rate of less than 12 cfm (0.028-0.057 m/minute) for a
minimum of 5 minutes, before starting any brazing or debrazing operation. Then allow it to continue to flow at
the same rate until all brazing or debrazing operations are completed. (See paragraph 5-9 for brazing or de-
brazing procedures.)
k. After installation brazing operations are completed, allow nitrogen to flow for a minimum of 5 minutes.
l. Close nitrogen cylinder valve, nitrogen regulator, charging manifold valve, and both high and low pressure ser-
vice valves on the unit.