SERVICE PURGING

TM 9-4120-425-14&P

REFRIGERATION SYSTEM SERVICING (PURGING) - Continued

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CAUTION

Nitrogen is an inert gas. However, it presents the danger of asphyxiation and

therefore, must be discharged in a ventilated location.

SERVICE PURGING

Verify that the system has been discharged using a manifold as described in WP 0049-00, proceed as follows:

See specific component removal/ repair instructions.

Be sure that refrigerant has been discharged. (See WP 0049-00.)

Connect the center hose from the charging manifold to a nitrogen regulator and dry nitrogen tank.

The hose from the high pressure service valve to the charging manifold must be connected.

The hose from the low pressure service valve must be disconnected from the charging manifold.

Both service valves on the unit will be open by virtue of hose connections.

Close the unused valve (suction) on the charging manifold, and open the one (discharge) with the nitrogen tank

hooked up.

Open the nitrogen cylinder valve and adjust the regulator so that less than 1-2 cfm (0.028-0.057 m3/ minute) of

nitrogen flows through system.

Check discharge from hose attached to the low pressure service valve to be sure that no oil is being forced out of the

system.

10. Allow nitrogen to sweep through the system at the rate of less than 1-2 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 WP 0051-00 for brazing/debrazing procedures.)

11. After installation brazing operations are completed, allow nitrogen to flow for a minimum of 5 minutes.

12. Close nitrogen cylinder valve, nitrogen regulator, and charging manifold valve.

13. Disconnect the hose from the nitrogen tank regulator.

14. When all repairs are completed, go to WP 0052-00 for leak test procedures.

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