TM 5-4220-225-14
CAUTION
Never exceed 5 psi pressure differential (P) per minute.
(7)
Open the helmet air supply valve (5) approximately one-fourth turn to establish a flow of 6 ACFM.
(8)
If helmet P is excessive before 6 ACFM is established, decrease the exhaust valve (4)and continue to
increase flow.
(9)
With exhaust valve fully open and air supply valve set at1/4 turn open, adjust pressure adjusting screw (6)
on exhaust valve to obtain 0.3 ± .05 psig.
(10)
Shut the helmet exhaust valve (4) and check the helmet P for a reading of 2.0 + 0.3 psig.
NOTE
Alternately open and shut the exhaust valve to ensure P readings are stable. It should
not be necessary to adjust helmet supply valve.
(11)
Leak test the helmet assembly.
(a)
Fully shut the helmet exhaust valve (4).
(b)
Check the entire helmet for leaks with liquid leak detector or soapy water.
NOTE
If a leak is detected, notify your supervisor.
(c)
Wash the helmet with freshwater.
(12)
Open the helmet exhaust valve (4).
(13)
Shut air supply valve (5).
(14)
Remove air supply source and disconnect from air supply whip (2).
(15)
Remove gage (3) from blanking plate quick disconnect (4).
(16)
Remove the blanking plate (1).
(17)
Disconnect air supply whip (2).
(18)
Install protective cap and gasket on air supply adapter.
2-19
