BELL JAR ASSEMBLY LEAKAGE TEST.- To perform a leakage test on the bell jar assembly, proceed as follows:

1. Remove the hose assembly and the nipple assembly from the bottom bell jar coupling C-1. Disconnect the opposite end of the hose from differential pressure connection NIP-7.

Table 11-2.-Troubleshooting Chart

2. Ensure that the differential pressure bleed valve V-7, the test pressure gauge to bell jar V-2, and the system bleed valve V-5 are closed. Open the differential pressure shutoff valve V-8.

3. Place the bell jar on the adapter fixture and secure it with a clamp. Now plug the bell jar top coupling C-2.

4. Open the oxygen supply valve V-6 slowly until 100 inches of H2O is indicated on the differential pressure gauge DF-1. By closing valve V-6, leakage will be indicated by a drop in pressure on DF-1. There must not be more than 2 inches of H2O in 10 minutes.

5. Close the oxygen supply cylinder valve and open the system bleed valve V-5 to bleed the system.

6. Secure all test stand valves. Leave the system bleed valve V-5 open.

CAUTION

WHEN THE TEST STAND IS SECURED, ALL VALVES WITH THE EXCEPTION OF THE SYSTEM BLEED VALVE V-5 MUST BE CLOSED. VALVE V-5 IS LEFT OPEN TO PRE-VENT THE ACCIDENTAL BUILDUP OF PRESSURE IN THE SYSTEM.

CLEANING

Clean all external parts, test adapters and connections, gauge glasses, bell jar, O-ring, and terminals of the liquid oxygen quantity gauge capacitor-type tester with a soft, lint-free cloth. The cloth may be dampened with oxygen cleaning compound (MIL-C-81302).

PERIODIC INSPECTIONS

Periodic leakage inspections are required to be performed weekly. A pressure regulator (R-1) setting must be performed weekly also. In addition to the inspection requirements, the test stand should be visually inspected for cleanliness, freedom from oil and grease, missing or damaged parts, and general condition.

TROUBLESHOOTING

Refer to table 11-2, Troubleshooting Chart, for probable trouble causes and remedies. Information in this chart is intended primarily to aid oxygen shop personnel in diagnosing problems most likely to be encountered in their daily use of the test stand. Refer to NAVAIR 17-15BC-20 for parts removal and replacement.

Upon completion of any maintenance actions, complete the maintenance forms outlined in the NAVAIR 13-1-6.4.