I understand that a diving company should take all actions to ensure that their product remains safe and in perfect order, so the user is not endangered.

Nonetheless, there are users that are more than capable of repairing or modifying equipment according to their needs. This is how some current manufacturers started in the business.

For those mechanics-oriented people, you’ll find that with proper training, self- studies, and curiosity, servicing your equipment, it’s at your reach.

This project begins when one solenoid of my CCR clogged. So, if you have an error in one of the “automatic pre-dive tests”, the unit will display an error code number of the failed test and it will shut down soon after. As wrote on the manual: “If a test fails, the test number flashes, and the “spinning wheel” indicator on the right side of the display is replaced by a flashing error code, indicating what aspect of the test failed”.

The standard response from the user is simple: first, check the state of the battery, that it is not under/over charged and that it does not require a learn cycle, so battery issue may lead to trouble. Second, reboot or reset the battery. After that, you need to consult the troubleshooting table.

One interesting suggestion is “reset system parameters”. In some cases, a test may fail because some of the user selected parameters have become corrupted. Thus, for certain tests, the Configuration PC software can be used to reset system parameters. So, it’s worthwhile to also do this before continuing.

If you are done with all the suggestions and the problem is not fixed, you need to download a logbook called “red”.

Red logbook is something like a “box” that registers all tests on your electronic CCR. You must send the file to Poseidon, and they will tell you if you can fix it or not.

DIY

Investigate what errors codes means and how to fix it

For example, in my case the unit got an error code on test fifty-three (53), which means that the unit couldn’t calibrate the sensors. This test is based on a few factors, such as:

• Temperature of the sensors
• Percentage of oxygen in the gases used
• Response time from a sensor
• Milli voltage reading

As it is written in the manual: “the test will start by injecting pure oxygen directly on the primary oxygen sensor for twenty (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 confirms 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.”

To resolve the problem:

• Verify that the gas cylinders are connected to the correct pneumatic blocks 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.
• If test failure persists, contact an authorized Poseidon Service Center for repair.

A clue to what’s happening is the sub-number test: 68. The complete error code number is 53-68. This secondary displayed number (68) means: “primary diluent high”. <<The unit is reading a low pO2 regardless of the amount of oxygen that the controller is injecting into the unit.>>

What is forcing the unit to keep a low pO2?

There are 4 solenoids in the unit, and the primary diluent solenoid is not closing, is leaking, thus no matter how much oxygen the unit injects the pO2 will not rise.

Solution: Replace the solenoid or >>

send the head back to HQ or a qualified technician to be replaced.

Which not all countries or regions have.

Sending the head back to HQ is costly and time consuming. At that time, being already a “regular” technician on the unit, I decided to take the matters into my own hands.

Do it at your own risk!

This article was wrote for educational purposes.

I disassembled the head, once the two main pieces of the head were apart; but both computer and electronics boards connected, I started the pre-dive tests. On the 53-68 test I could hear and felt the gas streaming from the solenoid without stopping. I identified the leaking solenoid. Now, I had to continue taking apart the head and electronics to get access to the solenoid and replaced it.

All the procedures must be executed carefully, taking special attention not to damage the electronics and cables.

Replace part number is: 0000-649

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