"Hot" First Stage

[halocline]

I won't say that it's impossible that I went into the water with the valve mostly closed. Mistakes happen. However, I've made almost 250 dives and never done that before. I was taught to open the valve all the way and then back it off 1/4 turn. In this case, I am 95% certain that it was open.

The needle didn't move until the pressure in the tank got low. As I understand it, if the valve were closed part way, the needle would move at any pressure. Or is that not correct? If it was a dumb@ss mistake on my part, I want to be reasonably certain. I can correct that, but I'd like to have faith in my gear.

I believe you did have the valve open. If the valve was almost entirely closed, you would have had problems far earlier than 52 minutes into the dive. I think it's HIGHLY unlikely that you turned (rolled) the valve off without knowing it, unless you were in a very tight spot, and I have a feeling you would have mentioned that.

A couple of questions:
1) Did you ever check the tank after the dive with another reg set? If so, did it breathe normally and how much gas was in the tank? I think that's pretty important info. Maybe something happened to the valve, I have no idea. But, if the tank is still around, check it out. If there's no air in it, probably what happened was that your SPG stopped working and you were basically out of air, that's why you couldn't get any. That would also explain the feeling that you thought you were so great on air consumption; you weren't, but your SPG wasn't working.

2) What exactly did the guy at the shop mean by "too much pressure in the 1st stage?" I assume he hooked it up to an IP gauge and that your IP was too high. Did he give you a number? If your IP spiked during the dive, you probably would have had a nasty freeflow instead of losing air supply to the 2nd stage. So it doesn't make sense to me. If I had to guess, I would suspect that your IP might be too high but it doesn't have anything to do with your problem on the dive.

 

[chrismortell]

You're correct in that I wasn't in a tight spot. We did check the tank with another reg set and it was down to 150 psi. I also put my reg set on another tank with known pressure and both SPGs should the same psi. The guy at the shop did hook it up to an IP gauge but I didn't ask for a number.

Is it possible that it wasn't the reg at all but maybe debris inside the tank valve?

It is also possible, as beanojones points out, that the DM or my buddy did it accidentally. I get the reg back today and plan to try it out in a pool before I take out in open water again. Thanks for all the input and advice. I know a lot more about regs than I knew before.

 

[Scared Silly]

Bad instructor/captain trick: When a just starting out DM is getting too full of himself, walk behind him and close his valve just before he jumps in. He's supposed to look at the gauge while taking a breath but rookies sometimes forget the basics. This trick also works on newbie instructors.

If someone did this to me as a DM they would find themselves 1) No longer diving on that boat for the rest of the trip 2) No longer diving on the boat on any future trip 3) Be met at the dock by the police with assault charges.


Sorry but there are much better ways to deal with someone too full of themselves ...

 

[pescador775]

Chris, I don't know about debris in the valve. High pressure air will blast just about anything through the fairly large pipe in a valve. However, rust and scale can't get through a screen as readily. If the inside of the valve were dirty, the tank would be suspect. It should get a visual anyway if the regulator check does not turn up anything new.

When I finish jamming and the tank is full I place a piece of tape over the orifice. Once, a guy hooked up his reg to a tank without removing the tape. He completed the dive that way. I did not realize what had happened until time to refill the bottle. The tape was still in place with a neat, round hole in the center.

 

[widget]

I would also go with the theory of the valve WAS open - in all my years of commercial diving I have never had an instance where the valve handle was turned closed by accident DURING a dive, I think its possible of course, but quite remote.

Lets eliminate possibilities -If the valve was only half a turn open, chances are you would have seen fluctuation on the SPG earlier, debris in the cylinder is a possibility, but would really only have jammed the valve orifice if you were swimming upside down at some stage, and it would need to be quite substantial, did you check your reg filter, it would show there as well.
Liquid in the cylinder is a possibility, but again, you would need to be upside down and the valve snorkel should prevent this been passed through into the reg anyway - but again it would need to be substantial liquid amounts - not that likely.!

Its very unlikely its the reg IP, it would have to be ridiculously low to cause that noticable difficulty in breathing - to be honest, I think you can discount that idea anyway.

If human error is not to blame, my suspicion is its to do with the valve / cylinder combination somewhere. Remove the valve and check the cylinder internally, revalve with another valve and try again - I really cant see it been the reg.

 

[Netsvan]

It is more of an solution to a problem that doesn't really exist. The idea was to prevent someone thinking it was closed and try to open it with too much force that could possibly damage the valve. If you open your own valve open it all the way, you will know its open. If someone volunteers to check it say no thanks it is already open.

This is usually taught to most people with valves for (especially with rubber gaskets) so that a person can feel the valve tension and now over tighten and break the gasket or lock the valve.
Post 1

 

[themagni]

I thought the idea of the 1/4 - 1/2 back off was to allow you to easily close the valve after the dive.

If you open it with too much force, you may have trouble closing it to take your gear apart. It can be quite tough on a cold day with wet, shivering hands.

It's the same reason why your water valves at home are backed off - so you can close them again when you have to.

 

[halocline]

You're correct in that I wasn't in a tight spot. We did check the tank with another reg set and it was down to 150 psi.

That's obviously the reason why you couldn't breathe; you were out of air. Your SPG wasn't working. If you were at depth, 150 PSI in the tank is probably less than IP, so the 1st stage HP seat/orifice did not close. That would explain why your SPG reacted to inhalation and exhalation. There was no seal between the HP and IP chambers in the 1st stage. An unpressurized 1st stage is open; it's the tank pressure that provides enough pressure to close the valve. A tank with less than IP will not provide the pressure to close it.

There's probably nothing wrong with your reg, but when you get it back, get the IP checked by a good tech; actually, you can do it yourself. You just need an IP gauge and a couple of tanks, one full, one at 500-700 PSI. It should "lock up" at whatever IP is right for the reg, probably about 130-140PSI. When you take a breath, it should drop, then immediately return to steady IP when you stop inhaling. If it creeps up a little, that's a problem. It should be the same with both a full tank and one with 500-700 PSI. The guy at the shop can probably do it while you're there, and you can look at the IP gauge.

 

[pescador775]

How is it that the gauge was reading 900 psi in the water and would drop to almost zero upon inhalation? Moreover, Chris' gauge was reading normally on the surface when matched against another. However, the tank press at that time was only 150 psi. I have never seen a gauge act like that but there is always a first time. I think that there may have been two problems occurring simultaneously but I don't know what that would be unless that little hole in the gauge port was clogged temporarily.

 

[Kevua]

I have seen the exact symptoms before. The problem I had was what someone previously said. The air got turned almost off by being in a tight spot or going down/up a rope and the rope turning the knob or me just being new and turning it off then a 1/2 turn on.

It was acting very weird, was breathing fine until I hit the 55' mark, then every time I would breath in it would get harder to breath and the PSI would move up and down.