Drager Questions

ERIK A

I love my Dolphin. I have had it for three years. Enjoy diving it and dont really want to move to CCR anytime soon. I have modded the dolphin first running sidemounted alum thirties and now steel 45s. I just seem to use more gas than I should and Im not sure why. The flowrates check out. Pos/Neg test all check out. I just cruise through gas faster than I think I should. Now, I have not messed around with running different gasses through the jets to optimize flow...yet. Im just wondering if it seems normal to cruise through 2500 psi of mix out of alum 30 in 25 minutes. Am I doing my math wrong? I am very confused but I do love my drager.

Erik

Lake_Tahoe_Diver

How often does the ADV activate? How tight do you have the OPV set? It sounds like you are dumping a lot of gas (depending on the orifice your are using of course, are you using a 32% or what?).

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Scuba Diving,the only sport where it is good to be in over your head....

ERIK A

im using the 32 percent jet and I have the OPV tightened to nothing with a bubble diffuser above the OPV.

ERIK A

I cant give a honest answer on the ADV today, but I will in the near future. I am in full check mode.

Erik

Lake_Tahoe_Diver

What is the flow rate for the 32% orifice when you test it. Base on some quick math converting PSI per minute to liters you seem to be a little fast on the flow, assuming you have good dive practice and are not doing a lot of up and down style of diving.


It seems that you might be using the ADV a lot more than you think. I had that problem when I dove the dolphin, had to change my breathing mind set from a deep slow breath to a more normal breath.

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Scuba Diving,the only sport where it is good to be in over your head....

kiwi_diver

From memory, the 32% flow rate is around 15 lpm and your 800 odd litres should last 50 minutes.

A good starting point would be to check your flow-rate with a flow meter. Jets can become blocked but they can also become enlarged through corrosion or damage.

I expect you're running wing inflation and maybe suit inflation off the same cylinder which will account for some loss.

What about your mask fit? if you're clearing it a lot, you'll be wasting gas and also you might, without realising it, be free flowing through your nose.

Cheers,

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Ray.
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Latitude 36 South, where the deeper you dive, the warmer it gets!
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ERIK A

I do check the flow rate every time I preflight the rig. I have a set of drager specific flow guages. Now the mask clearing may be something as well as the breathing. I do alot of OCdiving still and switch back and forth alot. That may very well be the issue. Im still checking. I appreciate the help from all yall. I have been perplexed as I am pretty carefull with the rig and check it rigourously. I will admit that I am still not 100 percent comfy on it and that may be why I use more gas as well. I love it and respect it. I just dont 100 percent trust it...even the dolphin.



Erik

kiwi_diver

There's nothing wrong with that, mate. Having a heathly respect for your breather and always being prepared for the worst will go a long way to keeping you alive and enjoying your diving.

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Ray.
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Latitude 36 South, where the deeper you dive, the warmer it gets!
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Diver Dude

Erik,

I had a similar problem with my Drager. Like you I bought it new in 2005. My buddy had one so I would always compare his gas usage to mine. He would always get around 30% better gas efficiency than me. My unit was like this from my first dive.
I thought I was clearing my mask to much, then I thought I was wearing the Drager to tight, then I thought it might be the bypass next I looked into the OPV. It was none of these. It was driving me crazy.
On my last dive last year I was doing the flow meter test. As always it checked out perfectly. For the hell of it I left the flow meter in the mass flow controller with the gas still on and walked away. Ten minutes later I checked the meter and that little ball was pegged against the top of the tube. I repeated the test and the same thing happened.
Over the winter I brought in to get repaired. The shop said the high pressure seat was shot. The repair cost $300 (Drager parts are expensive). I took the unit home, did the flow meter test a couple times and it seems to be fine. I haven't dove with it yet but when I do I'll let you know how it went.
I am convinced I bought a defective Drager. I only had about 60 dives on it and it never got good gas efficiency. My buddy has at least 300 dives on his unit and never had to replace the high pressure seat.

Good luck finding the problem.

Bryan

ERIK A

Bryan,
I feel you and I am glad I am not crazy. Still working it and I will post any updates. Its funny because what you describe is very close to how I feel things are going.
Erik