Question BC dump valves aren't working

[SonByrne]

I'm not sure what else to do at this point so I figured that I would post here.

I've had an Aqualung Dimension with an i3 for the last 2 years and it's been nothing but problems. For whatever reason, the dump valves don't work properly at depth and it's put me in dangerous situations more than once.

We took it to a dive shop, had it serviced, but the issue persisted. We had them test it and they didn't detect anything, but then we did a pool session and both an instructor and my wife said that it definitely wasn't letting air out at depth.

The shop sent it to Aqualung months ago and I just got a call today saying that they tested it and that there was nothing wrong with it.

The main problem is that usually, the dump valves don't work. This has sent me shooting to the surface on a few occasions (luckily not at any significant depth) and also makes it near impossible to achieve buoyancy. When it does finally dump air, it's almost always too much then I'm afraid of putting air in it because I know it's going to be tough to let it back out.

I originally thought I was just bad at diving since 2 of the times I went to the surface was during one of my classes. The instructor explained that I likely had too much air for the depth I was at, which caused the air to expand making me become more buoyant, which sent me closer to the surface so that I couldn't dump air fast enough to prevent myself from shooting to the surface.

Another instance where I had an issue was during a drift dive. I basically got stuck about 5-10 feet above the group. My wife was telling me to come down, but I for the life of me couldn't get air to dump so that I couldn't get to the depth of the rest of the group.

The only reason I figured out that it might be the BC was when I explained what kept happening to my wife, she said that the dump valves should always dump, tested it herself during a pool session and had the same issue. We then had an instructor take it down and he had the same problem.

So am I just screwed here? It doesn't seem like anyone can figure out what's going on with this thing, but there's definitely an issue based on other, experienced divers testing it out under the water. It just seems like Aqualung's tests didn't catch it.

 

[Marie13]

You need a new BC. Diving a BC that you can’t dump air when needed is dangerous. Why have you kept diving it?

 

[elan]

Another instance where I had an issue was during a drift dive. I basically got stuck about 5-10 feet above the group. My wife was telling me to come down, but I for the life of me couldn't get air to dump so that I couldn't get to the depth of the rest of the group.

That does not make sense to me. If you are below the surface and you need to get deeper, you do not dump air you just exhale and you will start sinking. Then as you arrive at the depth you need to ADD air to make yourself neutral.

, she said that the dump valves should always dump

This is not correct. Dump valves will only dump air if the air bubble is moved to the valve and is located at below at least he top edge of the valve (if its positioned vertically ) or below the valve when it's horizontal.

It's not clear what dump valve you are using , top , bottom or the inflator. Eech will require different techniques but on all the cases the air has to be moved to the valve before you can dump.

 

[Marie13]

This has the I3 lever on the left side. I believe that dumps air from all valves at once.

 

[parzdiver]

Get rid of the BC and get rid of the i3 system. There are some people that like it, but I have a friend that also had issues with hers. The theory behind the system sounds good, but it is a complicated system where the more simple hose dump and butt dump work fine and are simple.

 

[BRT]

I'm not sure what else to do at this point so I figured that I would post here.

I've had an Aqualung Dimension with an i3 for the last 2 years and it's been nothing but problems. For whatever reason, the dump valves don't work properly at depth and it's put me in dangerous situations more than once.

We took it to a dive shop, had it serviced, but the issue persisted. We had them test it and they didn't detect anything, but then we did a pool session and both an instructor and my wife said that it definitely wasn't letting air out at depth.

The shop sent it to Aqualung months ago and I just got a call today saying that they tested it and that there was nothing wrong with it.

The main problem is that usually, the dump valves don't work. This has sent me shooting to the surface on a few occasions (luckily not at any significant depth) and also makes it near impossible to achieve buoyancy. When it does finally dump air, it's almost always too much then I'm afraid of putting air in it because I know it's going to be tough to let it back out.

I originally thought I was just bad at diving since 2 of the times I went to the surface was during one of my classes. The instructor explained that I likely had too much air for the depth I was at, which caused the air to expand making me become more buoyant, which sent me closer to the surface so that I couldn't dump air fast enough to prevent myself from shooting to the surface.

Another instance where I had an issue was during a drift dive. I basically got stuck about 5-10 feet above the group. My wife was telling me to come down, but I for the life of me couldn't get air to dump so that I couldn't get to the depth of the rest of the group.

The only reason I figured out that it might be the BC was when I explained what kept happening to my wife, she said that the dump valves should always dump, tested it herself during a pool session and had the same issue. We then had an instructor take it down and he had the same problem.

So am I just screwed here? It doesn't seem like anyone can figure out what's going on with this thing, but there's definitely an issue based on other, experienced divers testing it out under the water. It just seems like Aqualung's tests didn't catch it.

I am going to repeat what Elan said. Do not dump air to go from one depth to a lower depth. Exhale and you should go down. Then at the lower depth you may need a little more air to maintain buoyancy. The inverse of this it you don't add air to go up. When you go up any air in your BCD or suit will expand and you likely have to dump a little. I am not talking about leaving the surface, and I am not telling you not to inflate your BCD once you are on the surface. I have never been around an i3 but the idea of lever up to go up and lever down to go down seems wrong to me.

 

[elan]

This has the I3 lever on the left side. I believe that dumps air from all valves at once.

Oh yeah thats the goofy system that Aq has come up with which is only relevant to floating and not diving

The air bubble location will still be crucial and I suspect this is why OP has difficulty using this BCD. If they think that to go down you need to press down and to go up you need to press up thats a very dangerous understanding. Because if pressing down means dumping and pressing up means inflating then its totally dangerous because thats a guarantee for a runaway accend.

And from reading the OPs post its a combination of both non understanding how the system works and how it affects the buoyancy and not locating the bubble properly what is causing the issues. He did say that when it dumps it dumps a lot. It sounds to me that at that stage the bubble moves to the dump and it works. At other times the bubble is elsewhere and nothing dumps obviously.

 

[Marie13]

Oh yeah thats the goofy system that Aq has come up with which is only relevant to floating and not diving

The air bubble location will still be crucial and I suspect this is why OP has difficulty using this BCD. If they think that to go down you need to press down and to go up you need to press up thats a very dangerous understanding. Because if pressing down means dumping and pressing up means inflating then its totally dangerous because thats a guarantee for a runaway accend.

The OP mentioned both his girlfriend and an instructor had issues dumping with this same BC. I’ve read of others with similar issues. A buddy of mine has had one for four years. Loves it. I have no use for the I3.

 

[elan]

The OP mentioned both his girlfriend and an instructor had issues dumping with this same BC. I’ve read of others with similar issues. A buddy of mine has had one for four years. Loves it. I have no use for the I3.

Well I am sure I will have issues with it as well if I was explained how it works based on how their elevator lever works The first time I heard about it I think 10 years ago it made me wonder if the engineer who invented it is actually a diver.

 

[undrwater]

Can the valves on those BC's be replaced with standard inflator and dumps? Probably cheaper than a new BC.

@SonByrne , does the instructor who had issues with this BC have experience with it? Do you have experience with a standard inflator / dumps? Was buoyancy easier in a different BC?

Assuming there's something wrong with the BC (and not you), it's probably going to be an uphill battle getting AL to agree, unless you can get the shop you bought it from onboard, or unless you find whatever the defect is that is creating the problem.