(3) Connect the vacuum pump (4) to the PUMP quick-disconnect fitting (5) on the test set.
(4) Open helmet air supply valve (6) at least one full turn.
(5) Turn VAC/AIR trigger (7) to VAC (straight up and down).
(6) Connect vacuum gage (8) to quick disconnect fitting (9).
(7) Operate the vacuum pump handle (10) until a 20-in. Hg vacuum is indicated on the vacuum gage (8).
Disconnect the vacuum pump (4) from the test set. This step eliminates the possibility of a leak through a
faulty vacuum pump.
(9) Observe vacuum gage (8); the gage should show no change in a 1-minute duration test.
If a noticeable change occurs (3 inches Hg), notify you supervisor.
Reconnect vacuum pump (4). Bleed off until the vacuum gage (8) indicates zero.
Turn the VAC/AIR trigger (7) to AIR.
Disconnect and stow the vacuum pump (4).
Remove vacuum gage (8) and stow.
Remove the air whip (1) from the helmet air adapter (2) and the test set adapter (3).
Reinstall the protective cap on the helmet air supply adapter (2) and the plugon the test set outlet (OUT)
Secure all equipment and stow as required.
b. Helmet P/Flow and Leak Test (figure 2-3).
Install blanking plate (1).
Remove the protective cap and gasket from the helmet air adapter and connect air supply whip (2).
Connect air whip to air supply of 100 psi.
Connect pressure gage (3) to quick disconnect on blanking plate (1).
Open exhaust valve (4).
Slowly open air supply valve (5) and check that the pressure gage (3)indicates the applied pressure.