2-6. Predive Setup Procedures - continued.
Table 2-2. Predive Setup Procedures - CONT
2. Connect and check emergency
e. Check that no air is escaping through the one-way valve by
air supply - continued
holding a moistened finger lightly to the main air supply inlet.
It is required that the emergency air supply be
worn on all dives to depths in excess of 60 feet. It
is recommended that it be worn on shallow dives
(less than 60 feet deep) as well.
f. Close the cylinder valve and the emergency air supply valve on
the side block. Wipe any residual moisture from the one-way
3. Connect and check main air
Never connect the main air supply hose (umbilical)
to the emergency air supply inlet. The emergency
air supply valve does not incorporate a one-way
valve to protect the diver from baratrauma
(squeeze) in the event of loss of pressure in the
a. Using the helmet adapter hose, connect the umbilical to the main
air inlet on the side block assembly.
Use two wrenches to connect the umbilical - one
to hold the adapter and one to turn the hose fitting
to prevent damage to the adapter threads.
Umbilical connection should be snug but not
overtight. Do not use excessive force or the
adapter will be damaged.
b. Turn on the main air supply from the surface support platform.
c. Slowly open the steady flow valve on the side block and check
for flow of air into the helmet.
d. Close the steady flow valve.
e. Momentarily depress the demand regulator purge button.
f. Turn dial-a-breath knob out until regulator freeflows, then turn
knob back in until it stops.
g. Extend the nose block device outside the mask.