User manual

Poseidon MKVI User Manual Appendix 1
Page 70
If you get an error on test 49
Test 49 is the Positive Pressure Loop test (PPLT) where the unit checks for leaks in the
breathing loop and if the solenoids are opening and closing they way they
should.
If your unit fails on this test, check the following:
- Is the OPV valve on the exhalation lung closed?
- Are all loop hoses connected?
- Are all o-rings in the loop undamaged?
- Are all o-rings in the loop mounted correctly?
- Is there any visible damage to the unit?
- Did the loop pass a negative loop test?
- Are the lungs empty when the PPLT starts?
- Is the bottom plate of the canister housing properly assembled with all four screws?
- Is the mouthpiece leaking?
The PPLT is a very sensitive test, where the unit looks for changes in pressure in the loop.
A failed PPLT can be caused by one or both lungs being pressed by the mouthpiece or any
other part of the unit.
Make sure that the lungs are kept free from any external pressure, during the PPLT.
We know from experience that almost all failed PPLT are caused by improper assembly of the loop.
Proper assembly of the loop, regularly lubricating o-rings in the loop and making sure that the
OPV valve on the exhalation lung is closed, rinsed with fresh water and cleaned will minimize
the risk of failing on test 49.
Error on test 53
Test 53 is the oxygen sensor calibration test and this is quite complicated and based on a lot
of factors such as:
- Temperature of the sensors
- Percentage of oxygen in the gases used
- Response time from a sensor
- Milli voltage of a sensor
The test will start by injecting pure oxygen directly on the primary oxygen sensor for 20 continuous
seconds. After the calibration constants for oxygen are established, the system then injects
diluent (air) via the diluent calibration solenoid valve. In doing so, this test calibrates the primary
sensor, and conrms that the correct gas mixtures are used in the respective cylinders.
This means, that the milli volt reading from a sensor alone can’t be used to establish if an
oxygen sensor is working properly or not. The response time of an oxygen sensor differs based
on the temperature of the oxygen sensor. This means that the temperature of an oxygen
sensor can have a big effect on the success of a Pre Dive calibration.
If your unit stops at test 53, try the following to resolve the problem:
- Verify that the gas cylinders are connected to the correct pneumatics block LP connections
(DIL/O2).
- Make sure the cylinders contain the correct gas mix
- If winter diving, warm the sensors up, in your pocket
If the unit keeps failing test 53, you might have to replace one or both oxygen sensors.
Once the service date is due, the diver is prompted to acknowledge (similar to “power up pro-
cedure”) that he/she has understood that service is needed. A grace period of 4 weeks is added.
The service due date can also be seen through the PC Cong PC software.
Depth reading difference
When you compare the depth reading on the Poseidon MKVI display and your wrist mounted
dive computer, placing them side by side, you might see a difference in depth. This is due to
the fact that the depth sensor in the MKVI is located at the bottom of the e-module, located
behind your neck and not in the display it self.
C1 alarms on land
When your Poseidon MKVI has passed the Pre Dive check you should always set the mouth-
piece DV switch to its Open Circuit (OC) position.
If you set it in Closed Circuit (CC) position, you will most likely get a C1 alert. This is normal.