Valve drill and free flow - possible cause?

[SpeedyJ]

Have a look at training material on erroneous and fixable failures. Your teammates should be able to help sort out the issue, or at a minimum be able to verify and communicate the issue to you.

In the game of resource management shutting down a post may preserve gas, but it removes a breathable second stage & inflation. If there’s a way my teammate can fix the issue and get that post back (i.e. fix the issue) we have more resources to safely conduct/conclude the dive.

 

[John C. Ratliff]

I’m wondering why you are doing this drill on a regular dive? Any time you depressurize a regulator underwater, you are introducing a potential for water (saltwater?) to get into the first stage, either through the second stage or from a loose first stage on the post. In other words, you are setting yourself up for a potential problem by depressurizing the regulator. Also, if you breath down the second stage all the way, you can potentially introduce a vacuum, sucking saltwater into the LP line and first stage. Finally, with a slight suction on the regulator from the LP hose you breathed down completely, if you then open the valve and pressurize the regulator, it will most likely free flow and cause the symptoms you are describing.

SeaRat

 

[Murre]

I’m wondering why you are doing this drill on a regular dive? Any time you depressurize a regulator underwater, you are introducing a potential for water (saltwater?) to get into the first stage, either through the second stage or from a loose first stage on the post. In other words, you are setting yourself up for a potential problem by depressurizing the regulator. Also, if you breath down the second stage all the way, you can potentially introduce a vacuum, sucking saltwater into the LP line and first stage. Finally, with a slight suction on the regulator from the LP hose you breathed down completely, if you then open the valve and pressurize the regulator, it will most likely free flow and cause the symptoms you are describing.

SeaRat

I am very curious to hear more about this since valve drills (GUE for example) includes breathing the second stage down to the click before switching to the backup.

This is done thousands of times every year around the world during training and also regular dives when one (including myself) wants to do spontaneous valve drills with the buddy before ending the dive for example - to keep skills up to date.

I'm thinking - if this was a big issue - GUE (and other organizations) sure wouldn't recommend training this way in doubles?

 

[BlueTrin]

I am very curious to hear more about this since valve drills (GUE for example) includes breathing the second stage down to the click before switching to the backup.

This is done thousands of times every year around the world during training and also regular dives when one (including myself) wants to do spontaneous valve drills with the buddy before ending the dive for example - to keep skills up to date.

I'm thinking - if this was a big issue - GUE (and other organizations) sure wouldn't recommend training this way in doubles?

It’s not a massive issue, but when it happened to me it happened when training with someone for Fundies using the above technique.

Only happened once out of many times and it was a continuous trickle of gas, not a dangerous one but fairly noticeable.

We went back to the surface and I actually asked him if he wanted me to retighten it and he told me to do it, we continued training on the 6m platform and it was uneventful.

I don’t think it would happen if you tighten a bit the first stage.