Cressi MC9 Manuel D'instructions page 73

56 SECOND STAGES
Opening and locking a common circular seal case regulator has
never been so easy as well as so safe. Every operation of check-
ing, servicing and setting of the second stage is made easier and
faster.
To reach this goal, we designed a revolutionary patented cap on
the device side, which avoids using a threaded coupling. The
valve as well can be serviced and set in an extremely easy way
guaranteeing the second stage utmost performance and perfect
tightness.
WARNING: the second stage can be opened, disassem-
bled and set only and exclusively at authorized Cressi-sub cen-
tres; the setting values CANNOT and MUST NOT be varied by
the user, so as not to affect the device performances. We de-
cline any responsibility for any operation carried out by unau-
thorized personnel.
NOTE: we recommend to have the regulator completely serv-
iced yearly or even oftener in case of intensive use; only origi-
nal Cressi-sub spare parts are to be used.
Visit our site www.cressi.com: you will find more information about
our equipment.
fig. 18
2.7 – XS2 2nd stage
Second stage supplies air "on demand", that is only when the
diver inhales from the mouthpiece, causing a slight vacuum insi-
de the regulator, which must be very slight in order not to make
breathing difficult. Such vacuum acts on the diaphragm, which is
sucked in towards the inside, causing the central plate to touch
the lever. The latter opens the air supply valve.
The valve of XS2 is composed of a renovated modular poppet in
plastic and chromium-plated brass, which is interchangeable
with previous models of XS range: on one side, it is connected to
the lever, on the other side, it houses a newly designed thicker
rubber pad, closing the new adjustable nozzle, through which
the air flows at a pressure by 10 bar (145 psi) higher than the
environmental.
The air contained in the nozzle pushes the pad, which is contra-
sted by the poppet' s spring.
Therefore, the renovated poppet "floats" between the push of in-
flowing air and the spring which, having a slightly higher
strength, closes the nozzle perfectly.
fig. 19