OUTWARD LEAKAGE TEST.- In performing this test, the relief valve is not covered. The allowable leakage through this valve at 17.0 inches H2O is included in the maximum allowable leakage of 120 ccm.

NOTE: This text uses the abbreviations lpm for liters per minute. Newer equipment and technical manuals may use the correct abbreviation, which is L/min.

Table 12-7.-Troubleshooting (Oxygen Supply Valve Leakage Test)

Table 12-8.-Inlet Pressure (Overall Leakage Test) ^{With the regulator still mounted in the} chamber, proceed as follows:

1. Place the regulator supply valve control lever in the OFF position, and the diluter control lever in the NORMAL OXYGEN position.

2. Connect the regulator outlet to the piezometer in the altitude chamber.

3. Connect a line from the LOW PRESSURE connection to the REFERENCE TAP inside the chamber.

4. Turn the test stand INLET PRESSURE ON/OFF valve to the OFF position.

Table 12-9.-Troubleshooting (Overall Leakage Test)

5. Adjust the LOW PRESSURE REGULA-TOR until 70 psig is indicated on the REGULATED LOW PRESSURE gauge.

6. Turn the PRESSURE SELECTOR valve to the H2O position, and slowly open the LEAKAGE CONTROL valve until 17.0 inches of H2O is indicated on PRESSURE/SUCTION manometer. By adjusting the LEAKAGE CON-TROL, you maintain 17.0 inches of H2O indication throughout this test.

7. If no leakage is indicated on the HIGH RANGE LEAKAGE rotameter, turn the LEAK-AGE SELECTOR valve to the low range position, and check for an indication of leakage on the low RANGE LEAKAGE rotameter. Allowable leakage is 0.12 lpm (120 ccm).

8. Switch the LEAKAGE SELECTOR valve to HIGH position, and close the LEAKAGE CONTROL valve.

9. Repeat steps 6, 7, and 8 with the diluter control lever in the 100-percent OXYGEN position.

10. If leakage is excessive, locate its probable cause using troubleshooting chart, table 12-10.

SECOND STAGE RELIEF VALVE TEST.-

To perform the second stage relief valve test, proceed as follows:

1. Turn the PRESSURE SELECTOR valve to the Hg position, and place the FLOW SELECTOR valve in the CONTROLLER position.

2. Ensure the diluter control lever is in the 100-percent OXYGEN position.

3. Using the VENT PRESSURE valve, slowly apply 3 inches of mercury to the regulator outlet. The regulator relief valve should be venting at least 45 lpm, as indicated on the vent flow manometer.

4. Close the VENT PRESSURE valve and bleed the pressure down to 0 in Hq using VENT AMBIENT valve. Close the valve.

Table 12-10.-Troubleshooting (Outward Leakage Test)

5. Turn the FLOW SELECTOR valve to the REGULATOR position and close the VENT AMBIENT valve.

6. Slowly move the PRESSURE SELECTOR valve to the H2O position.

7. Turn the LEAKAGE SELECTOR valve to the LOW position.

8. Open the LEAKAGE CONTROL valve. Apply and maintain 17.0 inches of H2O to regulator outlet. Maximum allowable leakage is 0.12 lpm (120 ccm).

9. Close the LEAKAGE CONTROL valve.

10. Back out on the LOW PRESSURE REGULATOR and bleed the pressure with the SYSTEM BLEED valve.

11. Turn the LEAKAGE SELECTOR valve to the HIGH RANGE position.

12. If excessive leakage is found, locate the probable cause using the troubleshooting chart, table 12-10. If the relief valve does not vent, locate the probable cause by using the troubleshooting chart, table 12-11.