3S Full Face Mask – Negative Pressure
13
Maintenance
GB
5.3
Maintenance of the Exhalation Valve
In case of a leak remove the exhalation valve disc and replace it with a new one as follows:
(1)
Remove the protective housing.
(2)
Remove the exhalation valve disc or
(3)
remove exhalation valve. For this purpose unscrew the threaded socket from the mask inside
with the special tool.
(4)
Replace the defective components.
(5)
Reassemble the parts in reverse order.
(6)
Perform a tightness test [
chapter 5.5].
WARNING!
The air vents of the protective housing are turned to the front side. After maintenance the protective
housing must be fitted in the same position.
5.4
Replacing the Speech Diaphragm
(1)
Unbutton the nose cup.
(2)
Unscrew the threaded socket from the mask inside with the special tool.
(3)
Remove the speech diaphragm.
(4)
Assemble the new speech diaphragm with the gasket towards the connector.
(5)
Perform a tightness test [
chapter 5.5].
5.5
Tightness Test of the Mask
(1)
Fit mask tight onto the test instrument.
(2)
Generate a negative pressure of 10 mbar.
(3)
Measure the pressure change after 1 min.
The mask including the exhalation valve meets the requirements if for a moistened exhala-
tion valve and a negative pressure generated inside the mask the pressure change does not
exceed 1 mbar in a minute.
Leaking masks must not be used.
The year of manufacture is located on the valve disc.
The year of manufacture is located on the speech diaphragm.
The testing of the masks for tightness is performed using an applicable MSA test device
in accordance with the relevant operating manual.
