SERVICE LEAK TEST - Continued

TM 9-4120-425-14&P

REFRIGERATION SYSTEM SERVICING (LEAK TEST) - Continued

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SERVICE LEAK TEST - Continued

Testing Procedure - Continued

If a leak is found, discharge and purge the system and repair leak. See specific instructions for components to

be removed.

If a leak was not found and refrigerant-22 was used to pressurize the system, see charging instructions (See WP

To pressurize a system that has been discharged and purged for leak testing with an electronic detector:

Remove the hose connection protective caps from the high and low pressure service valves.

Connect the hoses from a charging manifold to the service valves.

Connect a cylinder of refrigerant-22 to the center hose connection of the charging manifold.

CAUTION

Connect the refrigerant-22 cylinder so that only gas will be used for pressurization.

Open both unit service valves and the charging manifold valves.

Open the refrigerant cylinder valve slightly and adjust as necessary to prevent formation of frost, and allow

system pressure to build up until the gauges read 40-50 PSI (2.8-3.5 kg/cm2).

Close the charging manifold valves and the refrigerant cylinder valve.

Remove the refrigerant-22 cylinder from the center hose connection.

Connect a nitrogen regulator of dry nitrogen to the center hose connection.

Open the charging manifold valves and the nitrogen cylinder and regulator valve. Allow system pressure to

build up until gauges read 300 PSIG (21.2 kg/cm2).

Perform leak tests, then discharge and purge the system, in accordance with WP 0049-00 and WP 0050-00

before performing maintenance, or before evacuating and charging the system, as appropriate.

Final leak testing. Always perform a final leak test after performing any repair or replacement of components before

the air conditioner is reassembled and the refrigeration system is evacuated and charged.

END OF TASK

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