MANOMETER PREPARATION

Maintenance on the 1172AS100 begins as soon as the test stand is uncrated. You should fill the OUTPUT, INPUT, and VENT FLOW manometers with a liquid that has a known specific gravity of 1.0. The liquid used for the 1172AS100 is a mixture of one part concentrated green manometer fluid (merian D-2930) mixed with 10 parts of water. To fill the manometers, your first step is to adjust the scale so that the zero is located half way between the full-up and the full-down position.

Remove the fill plugs from the manometer reservoirs and fill the reservoir until the fluid reaches the zero mark on the scale. After you have filled the reservoir to zero, replace the fill plugs.

To fill the pressure suction manometer with fluid, use red manometer fluid with a specific gravity of 1.9. The procedure is the same. Adjust the scale so the zero mark is half way between the full-up and full-down positions. You have one more type manometer to fill. The Hg manometer uses triple-distilled mercury. To fill this manometer, follow the same procedure that you used for the other manometers. Do not spill the mercury. If you do, notify your supervisor, and follow the special precautions for cleaning mercury spills.

PRESSURE/LEAKAGE TESTS

To ensure maximum operating efficiency, pressure/leakage tests must be performed periodically.

NOTE: Use systems schematic drawings as an aid in determining any malfunctions that may exist. You can find these schematics in NAVAIR 13-1-6.4.

Outward Leakage Test (Supply System)

The outward leakage test (fig. 11-1) is performed as follows:

1. Ensure the supply cylinder valve and all test stand valves are closed.

2. Open fully, then close the supply cylinder valve.

3. Note the pressure registered on gauge (9). After 2 minutes, reread the pressure on gauge (9). There should be no pressure drop (a drop in pressure indicates leakage).

Outward Leakage Test (Regulated High-Pressure System)

The outward leakage test is performed as follows:

1. Cap connection (18) in chamber.

2. Open supply cylinder valve.

3. Turn regulator (Q) to LOAD, and hold until 2,000 psig (or cylinder pressure) is indicated on gauge (10). The regulated low-pressure gauge should indicate the gauge guard cut-off pressure, 170 5 psig.)

4. Close the supply cylinder valve and note the pressure on gauge (10). After 2 minutes, reread gauge (10). There should be no pressure drop (a drop in pressure indicates leakage).

NOTE: If pressure is registered on gauge (27), a leak is indicated in ON/OFF valve (L) or ON/OFF valve (G). A pressure drop on gauge (11) also indicates valve (G) is leaking. Valve (G) will be independently tested later.

Bleed pressure by turning (Q) to VENT. Open valve (S) to bleed system, then close valve (S).

Outward Leakage Test (Regulated Low-Pressure System)

The outward leakage test is performed as follows:

1. Open the supply cylinder valve. Turn the selector valve (F) to HIGH and the selector valve (D) to Hg.

2. Turn the ON/OFF valves (L) and (G) to ON.

3. Slowly turn the regulator (N) clockwise until 70 psig is indicated on gauges (1 1) and (27).

4. Return valve (L) to OFF and observe rotameter (8). Any leakage will be indicated by the ball rising in the rotameter tube. There should be no leakage.

5. Turn valve (F) to LOW RANGE position and observe rotameter (7). There should be no leakage.

6. Return valve (F) to HIGH RANGE, and valve (L) to ON.

7. Slowly adjust the regulator (N) until 160 psig is registered on gauge (11). Gauge (27) should indicate its gauge guard cut-off pressure of 145 5 psig.

8. Turn the ON/OFF valve (L) to OFF and observe rotameter (8). There should be no leakage indicated.

9. Turn the selector valve (F) to LOW RANGE and observe rotameter (7). There should be no leakage indicated.

10. Decrease the pressure to 70 psig by opening valve (S), and turning regulator (N) in a counterclockwise direction.

Leakage Control Valve (E) and Leakage ON/OFF Valve (G) Tests

Perform leakage control valve and leakage ON/OFF valve tests as follows:

1. Connect a hose from connection (19) to tap (20) in the chamber, and observe rotameter (6). There should be no leakage indicated.

2. Turn the ON/OFF valve (G) to OFF and remove the cap from connection (18) in chamber.

3. Observe rotameter (7). There should be no leakage indicated.

Suit Simulator System Leakage Tests

Perform leakage tests on the suit simulator system as follows:

1. Open the shutoff valve (R) and valve (J) fully. Place the selector valve (0) to the ALT CHAMBER, and valve (M) to the suit simulator position.

2. Remove the hose from tap (20) and connect it to tap (21) (connecting connection (19) to tap (21)). Cap piezometer (26).

3. Place selector valve (D) in the H2O position, and valve (F) in the HIGH RANGE position.

4. Open valve (E) slowly to maintain a pressure of 10.0 inches H2O throughout the system as indicated on manometer (4). Close valve (E). Any further climb on manometer (4) indicates a leak through valve (H).

5. Open valve (E) to maintain 20.0 in. H2O. When pressure is constant, observe rotameter (8). There should be no leakage.

6. Turn valve (F) to LOW RANGE. The rotameter (7) should indicate no leakage.

7. Return valve (F) to HIGH RANGE, and close valve (E). Remove the hose from connection (19) and allow the pressure to escape from the hose.

NOTE: Open valve (C) to aid in relieving pressure; then close it.

8. When the pressure has equalized, connect the hose from tap (21 ) to tap (20) in the chamber. Rotameter (6) should show no indication of leakage.

9. Remove the cap from Piezometer (26), and disconnect the hose between taps (20) and (21) in the chamber.

10. Turn the regulator (N) counterclockwise, and open valve (S) to bleed system. Close all test stand valves with the exception of valves (R) and (J).

Altitude Chamber and Suit Simulator Tank Inward Leakage Test

Perform the altitude chamber and suit simulator tank inward leakage test as follows:

1. Place valve (D) in the Hg position. Ensure the ON/OFF valves (G) and (L) are in the OFF position. Place valve (0) in the suit simulator position.

2. Close the chamber door and turn the vacuum pump motor ON.

3. Open the VACUUM CONTROL valve (B1) and "ascend" to 30,000 feet. Close (B1) and check to ensure that the same altitude is indicated on both altimeters (12) and (13). At 30,000 feet you will see the high-range altimeter start to climb and at 40,000 feet the low-range altimeter will no longer be in use. This happens automatically and the low-range altimeter will not be damaged.

4. Using valve (B1) "ascend" to 40,000 feet;

ensure that altimeters (12) and (13) register the same altitude. 5. Using the VACUUM CONTROL valve (B1), ascend to 52,000 feet. (Altitude is indicated on altimeter (12).)

6. Close (B1); after a 2-minute stabilization period, record the altitude indicated on altimeter (12). Altitude "loss" should not exceed 1000 feet in 20 minutes.