OVERLOAD TEST. To perform the overload test, proceed as follows:

1. Cap the regulator inlet and attach the regulator outlet to the short hose attached to piezometer (26) in the chamber. Ensure all test stand valves are in the secured position, then open the N2 supply cylinder valve.

NOTE: Ensure the regulator outlet and piezometer (26) are one inch apart.

2. Using the hose supplied with the test stand, connect LOW PRESS connection (19) to REF. TAP connection (21) in the chamber.

3. Ensure the FLOW SELECTOR valve (M) is in the REGULATOR position.

4. Adjust LOW PRESS. REGULATOR (N) so that regulated LOW PRESS. gauge (11) indicates 70 psig.

NOTE: When the in-system leakage rotameters are used, an inlet pressure of 70 psig will normally be used, as this is the pressure used to calibrate the rotameters.

5. Place PRESS. SELECTOR valve (D) in the Hg position.

6. Slowly open LEAKAGE CONTROL valve (E) until 1.85 inches in Hg is indicated on Hg manometer (5). Maintain 1.85 inches of Hg for 2 minutes. If no leakage is indicated on HIGH RANGE LEAKAGE rotameter (B), turn LEAK-AGE SELECTOR valve (F) to the LOW RANGE position and check for leakage on the LOW RANGE LEAKAGE rotameter (7). The maximum allowable leakage will be no more than the allowable leakage for each model shown on the performance test sheet. If the leakage is excessive, dispose of the regulator in accordance with your local directives.

NOTE: A body leakage testis done on the model 900-002-025-05 regulator only. Refer to the NAVAIR 13-1-6.4, DEMAND VALVE LEAKAGE TEST.

WARNING

NEVER BLOCK THE OUTLET OF THE MINIATURE REGULATOR WHILE A PRESSURE IS APPLIED TO THE INLET. THIS WILL SERIOUSLY DAMAGE THE REGULATOR.

NOTE: If a high reading is encountered during this test, make sure the pressure breathing aneroid is not screwed into the regulator housing too far before disposing of the regulator. Turn the pressure breathing aneroid counterclockwise out of the regulator housing and then recheck the readings.

7. Disconnect the hose from LOW PRESS connection (19) and REF TAP connection (21) in the altitude chamber.

8. Uncap the regulator inlet and connect the altitude chamber. regulator inlet to N2 input connection (18) in the

9. Ensure PRESS SELECTOR valve (D) is in the Hg position.

10. Turn on the vacuum pump.

11. Turn INLET PRESS on/off valve (L) to ON slowly.

12. Using LOW PRESS REGULATOR (N), apply 110 psig to the regulator inlet. The pressure will be indicated on N2 INPUT PRESS gauge (27).

13. Open OUTPUT valve (C) to draw a flow through the regulator, then close valve (c).

14. Place PRESS SELECTOR valve (D) in H2O position. Observe the PRESS/SUCTION manometer (4) for 5 minutes. The pressure must not exceed 2.5 inches of H2O. After the 5 minute period, read manometer (4) and enter the reading on the performance test stand. If the leakage is excessive, dispose of the regulator.

15. Leave the positions of all controls and connections unchanged.

SAFETY PRESSURE TEST. To perform the safety pressure test, proceed as follows:

1. Adjust LOW PRESSURE REGULATOR gauge (27). (N) to 50 psig as indicated on N2 INPUT PRESS

CAUTION

OPEN FLUTTER DAMPENER VALVE (J) 1/4 TURN. IF THE REGULATOR CAUSES THE FLUID IN PRESS/SUC-TION MANOMETER (4) TO FLUTTER, OPEN FLUTTER DAMPENER VALVE (J) SLOWLY UNTIL THE FLUTTER IS ELIMINATED. IF AT ALTITUDE DESCEND TO SEA LEVEL PRIOR TO OPENING VALVE (J) AS THE PRESS/ SUCTION MANOMETER CAN BE EASILY OVERLOOKED. WHEN ASCENDING TO ALTITUDE MAIN-TAIN AN OUTPUT FLOW OF 6.0 INCHES OF H2O.

NOTE: When increasing flows the inlet pressure must be adjusted to maintain the correct inlet pressure on N2 INPUT PRESS gauge (27).

2. With OUTPUT valve (C) closed, read PRESS/SUCTION manometer (4) and enter the reading in the appropriate block on the performance test sheet.

3. Adjust OUTPUT valve (C) to the equivalent of 100 lpm as indicated on the OUT-PUT manometer (1). Read the safety pressure as indicated on the PRESS/SUCTION manometer (4) and enter this figure on the performance test sheet. The safety pressure must not be less than 0.50 nor greater than 2.5 inches in H2O for all flows.

4. Adjust low-pressure regulator (N) to 90 psig as indicated on the N2 INPUT PRESS gauge (27).

5. Repeat steps 2 and 3.

6. Close the altitude chamber door.

7. Ensure that REF PRESS SELECTOR valve (O) is in the ALT. POSITION.

NOTE: A 6.0-inch flow in H2O must be drawn with OUTPUT valve (C). Open FLUTTER DAMPENER valve (J) 1/4 turn.

8. If the altitude chamber is inadvertently taken above the test altitudes, open chamber bleed valve (K) slowly and descend to the desired altitudes. Close valve (K).

9. Using VACUUM CONTROL valve (B), ascend to 34,000 feet as indicated on LOW RANGE ALTM. (13).

10. Repeat steps 1 through 5.

NOTE: If low safety pressure is encountered, dispose of the regulator. If high safety pressure is encountered at 34,000 feet, before disposing of the regulator ensure that the pressure breathing has not cut-in before 35,000 feet giving a false indication of high safety pressure.

11. Leave the position of all controls and connections unchanged, and continue to the pressure breathing test.

PRESSURE BREATHING TEST. To perform the pressure breathing test, proceed as follows:

NOTE: If problems are encountered during this test, refer to pressure breathing troubleshooting table 12-2 for adjustment of the pressure breathing aneroid.

1. Open OUTPUT valve (C)and draw a flow of 6.0 inches in H2O through the regulator. Using VACUUM CONTROL valve (B) ascend to 35,000 feet as indicated on the LOW RANGE ALTM. (13).

Table 12-2.-Troubleshooting (Pressure Breathing Test)

2. Using LOW PRESS. REGULATOR (N), adjust the inlet pressure to 90 psig. Close OUT-PUT valve (C).

3. Read the PRESS/SUCTION manometer (4). The reading must be between 0.50 and 3.5 in H2O. Enter this reading in the appropriate block of the performance test sheet.

4. Adjust OUTPUT valve (C) to a flow of 100 lpm and read the PRESS/SUCTION manometer (4). The reading must also be between 0.50 and 3.5 in H2O. Enter this reading on the test sheet also.

5. Increase the altitude to 43,000 feet, as shown on the HIGH RANGE ALTM. (12), and repeat steps 1 through 3. The readings on PRESS/SUCTION manometer (4) must be between 9.2 and 12.5 in H2O.

6. Increase the altitude to 50,000 feet. The H2O at this altitude. readings must be between 14.0 and 18.0 in 

7. After the completion of this test, leave OUTPUT valve (C) slightly open, and open CHAMBER BLEED valve (K) and return to sea level.

8. Open the chamber door and close valve (C). Turn off the vacuum pump.

9. Turn ON/OFF valve (L) to OFF, and remove the regulator from the test stand.

10. Close the N2 supply cylinder and, using LOW PRESS. REGULATOR (N) and SYSTEM BLEED valve (S), relieve all the pressure in the test stand. Secure all the test stand valves.

11. If the aneroid should need adjusting, loosen the aneroid lockscrew using a .035 Allen wrench and adjust the aneroid assembly using retaining pliers in accordance with the pressure breathing test troubleshooting table 12-2.

NOTE: Remember we are discussing the model 29267-A1 regulator only. For other models of the CRU-79/P miniature regulator, you must refer to the NAVAIR 13-1-6.4 manual.

After the completion of all the tests, you must purge the regulator with aviator's breathing oxygen for 1 to 3 minutes at 90 psig to the regulator inlet.

WARNING

NEVER BLOCK THE OUTLET OF THE MINIATURE REGULATOR WHILE PRESSURE IS APPLIED TO THE INLET. THIS WILL SERIOUSLY DAMAGE THE REGULATOR.

After completion of the oxygen purge, place the regulator in a plastic bag for storage.