User manual
Poseidon MKVI User Manual
Chapter 2
Page 43
Figure 2-8. Tests 44 and 45, conrming sufcient gas supply pressures.
DANGER:
Always open the oxygen cylinder valve slowly. Rapid pressurization
increases risk of re. Opening the valve slowly reduces this risk.
Carefully maintaining clean oxygen regulators, cylinders, and valves
before, during, and after your dives will further reduce this risk.
WARNING:
Once both cylinders have been turned on during Tests 44 and 45,
do NOT turn them off again until after completing the dive. If they
are turned off before completing the pre-dive routine, then Tests
49 and/or 53 will fail. If they are turned off before the dive, the dive
will be cut short. This is particularly true for the diluent cylinder,
which provides breathing gas in the event of an emergency open-
circuit bailout.
Oxygen and diluent cylinder supplies (test 44 & 45)
Tests 44 and 45 determine whether the Oxygen and Diluent cylinders, respectively, are turned
on and have sufcient gas to conduct a dive. Following proper procedure, both cylinders will have
been in the off position when Test 44 is reached (if not, gas will be wasted during Tests 24–27,
which verify that the four solenoid valves draw the correct amount of power when held open).
Each of these two tests will allow up to two minutes to turn on each cylinder. The bottom one,
two, or three segments of the respective cylinder pressure bar graphs will ash until sufcient
pressure is detected (Figure 2-8). When the system detects sufcient oxygen pressure, it then
waits until it detects sufcient diluent pressure. Provided the oxygen cylinder pressure is
greater than 34 bar / 493 psi, and the diluent pressure is greater than 51 bar / 739 psi, the
automated pre-dive check will pass, the pre-dive test routine will continue. There is no upper
limit for cylinder pressures for these two tests. However, it should be noted that the high-
pressure sensors themselves have an upper limit to the pressure they can correctly read. The
high-pressure sensor for the oxygen cylinder is limited to 207 bar / 3097 psi, and the sensor
for the diluent is limited to 300 bar / 4410 psi. Exposing either sensor to a pressure in excess
of these limits may yield unpredictable results. Also, oxygen pressures in excess of about 135
bar / 2000 psi pose a substantially increased risk of re.