Karlīs Rebreather Page
This is not a compleate list of checkprocedures, only some hints !
Some of the procedures described here may not fit for your device !
- Visual Check: do all parts look good (no cracks, mouse-bites, no chance for animals to move into the loop (imagine what happens if you get a cockroach in your mouth at 30m)) ?
- Ashure not to get hurried when doing the checks, it's your live that depends on your equipment.
- Measure what Gas (e.g. %O2) is in your Bottles.
- Check your scrubber.
- Check your direction valves: visual- and "cheek-test" (="hickey-test").
- Check all clamps, screws and valves.
- Check/adjust your ppO2-Sensors.
- If you ride a CMF-SCR check the flow-rate. You can simply add this check to the sealing test of every dive: beween the "vacuum" and the pressure test let the CMF flow and mesure the time until the counterlungs are filled. After the test you can use the gas to rinse the air out of your own lungs and start your dive.
- If you ride a ECCR check your 1st Stage Pressure on the O2 Side regulary,
if the pressure climbes too high the solenoid-valve can't open.
The higher the interstage pressure the more work is required of
the solenoid to open. This reduces the battery life and if the
battery is low can mean that the solenoid fails to open.
- Pre-breathe the absorbent to get the reaction going. Roughly 10°C more lime temperature double the reaction speed. Performing a "5-minute" pre-breathing is also a matter of safety. When perfoming such a "Suckstart", you have to think about getting into a sweat.
- Use your ears, does everything make the accurate sound and with the frequence it should ?
- If you ride a CMF-SCR check the flow-rate. You can compare the bubbles and the pressure gauge (a) with your buddy and (b) with what you expect.
- Read your ppO2 Displays often enouth (at minimum half the time that would be needed to bring your ppO2 from the setpoint to 0,21bar in case of an error).
- Want to check your ppO2-Sensors during dive ? No problem, just do a "Clusterflush" and apply a known Gas to them, so that you know what the display-reading should be. As an example: if your Diluent is Air (21% O2) and you are diving in 38m, closing the Valve of the O2-Bottle breathing from the Rebreather, exhaling into the water and getting the fresh gas out of the diluent bottle should bring you soon a reading of something near ppO2=1bar. Perform so that the displayed value has to change during the test.
- When the sensors age they will loose the linearity,
so you should check from time to time what ppO2 is reached when your display shows the value 1.3 ....
If you fly an ECCR to perform this test simply start the dive in the pure-O2 mode, so that Pamb = ppO2
and check what happens. It is quite easy to reach "pure Oxygen" at the surface, when you start from being already stable at ppO2=0,7bar, just check it out !
- RB rule # 1: anytime you feel unusual bailout.
- Check the Flow of every choke (measure it, especialy if you use an active-flow-SCR).
- Check your lime, did you get water in it by a fault, if so is there something to fit ?
- Clean and completly dry your loop, check if all parts are looking good.
- Make your rebreather storable, think about the needs of the material (Talkum for the Rubber, no sharp bents, good storage place), take care that no animals can move into the loop
- Check your Checklists, can you make them better ? it's a lot easier to find solutions when seated in front of a computer than when you are stuck in the real situation.
- Check your Hardware-Configuration, can you make it better (=safer, more reliable, easier to handle & neater) ?
Examples: does your ECCR have a sufficient Bailout regulator for every bottle with breathable gas ? Did you protect your bailout regulators with a Free Flow Control Device (for example the one delivered by Apeks) ? Can you identify anything in 0-vis ?
http://Rebreather.de/rebreather/checks.htm © Karl Kramer, 9.10.1998