regulator problem ???

[Zung]

Lemme re-phrase that:

"That's the way to tune a second stage, but remember to press the purge before you turn the orifice, and release the purge afterward." OK?

 

[300bar]

Way better

But I'll stick with my dunking the reg to check the cracking pressure.
Adjusting is a whole different story.

 

[waynne fowler]

Or maybe not, if you've done a comparative test with the Apeks.

The Apeks, being a more advanced "balanced poppet" design, should breathe "noticeably" better, but not "astoundingly" better. Try to tune your reg a bit: remove the hose (hard part, needs proper tooling or a rag), rotate the orifice inside 30° or so counter-clockwise, put the hose back (finger tight's OK), pressurize, repeat until it free flows, then back up a bit. Test with the manometer. I prefer it to the bucket of water because 1st it's less messy, then it gives a repeatable number for further reference.

Sorry Zung...
but I would disagree with your method of adjustment as you've omitted some very significant steps that could cost the op some unnecessary expense replacing parts that could be ruined following this method.

I would recommend that ashber you take your reg to a qualified service technician and have them adjust it for you, there's a bit more to tuning a reg than just turnin' a few screws and dropping it in a bucket of water.. Several adjustments need to be made in unison to get everything working properly... I'm not saying that you can't learn to do this stuff, but it's not really something you want to 'play around with hoping to get it right'. A good tech will not only adjust it for you but will take the time to show you what to do and why. Other tech's may want to charge a bit to educate you... pay it... it'll be worth the money to be more self sufficiant.

jm2c

 

[knowone]

Is your instructor for rent, or for sale.
I see a groovy, business opportunity.

Including car washer, or drone pilot?

Anyhow all will soon be good despite.

 

[globalmark]

I would recommend taking it either to your Dive centre or another one close By and asking them to Stick a Intermediate Pressure gauge on the Regulator (unless you have a Friend with one or you want to Buy one around $20-$30)
This will tell you if the Correct Pressure is Leaving the first Stage (99% regs are approx between 10.5-11.5 bar) and all Manufactures set this to there specified Level which is usually very easy to Breath . I set mine and regs for my Collegues (all working Diving Instructors) a lot lower as we think Manufactures are usually to easy to breath and also reduces our air consumption (Though I do not recommend Anyone doing this Unless really Know what they are doing and very experienced Divers) (I am a EXP Reg tech serviced and fixed 1000's Regs
Anyway The Intermediate Pressure gauge will tell if there is a Problem with the first stage or if it's set at the correct pressure - a Good reg Tech should be able to Plug one in and Know the Problem within 1 min.
if not a First stage Reg Problem then could be 2nd stage and if thats not the Problem then it's you..
Hope that Helps

 

[halocline]

There's probably nothing wrong with the regulator. Cracking pressure will have very little to do with a feeling of not getting enough air at depth. What the OP described is a classic description of a tank valve partially opened, and the bit about the 1/4 turn makes it more likely IMO that that's what happened. Just open the valve all the way and forget about it.

There might be some crud in either the valve or first stage filter, but that's a long shot.

The R395/295 is a downstream design 2nd stage, not balanced, but it provides plenty of air unless it's really badly out of adjustment, and that would be obvious at any depth. The MK17 is a very high performance 1st stage with excellent IP recovery and stability. Plus, I didn't notice any direct comparison between the two regs at the same depth on the same dive, so IMO there's little evidence that something is wrong with the reg.

Adjusting the cracking pressure on this 2nd stage is a bit more complicated than on the barrel poppet regs, because once you adjust the orifice, you have to then re-adjust the lever height. That's not too difficult, but it does mean either removing the plug on the side of the reg or the diaphragm, and sneaking a 1/4" nut driver in there. That's assuming the reg hasn't changed from the R190. So it's probably a good idea to find someone with some experience to do it, although simply taking it to a dive center does NOT mean you'll get someone that knows what they're doing. Maybe you will, maybe you won't. The certification process for regulator techs is hardly a reliable bar.

 

[Zung]

... as you've omitted some very significant steps...
jm2c

halocline and others are absolutely right in the sense that, formally, adjusting the orifice requires an adjustment of the lock nut to get the lever haight right.

My suggestion is based on the fact that if the original setting is nearly right, fine tuning the cracking pressure is a matter of 1/12 to 1/8 of a turn, and that wouldn't significantly affect the lever height. The OP, being a hydraulic engineer, should have more than enough capability to deal with this himself... Unless they teach management in engineering classes nowadays?

Recently, I've seen quite a few brand new straight out of the box Aqualung seconds badly tuned, free flowing or hard to crack. Every time, a little tweak of the orifice get them right. I hope Scubapro is not going in that direction.

 

[DevonDiver]

How does a tank valve only get partially opened? By forgetting (or being unaware) that it was already opened, and then closing it and then opening 1/4 turn.... many divers are taught to "open all the way, then back off 1/4 turn" to prevent the valve sticking open. I feel this is a mistake, and really only applied to OLD valves many years ago. The valve should be fully open, or fully closed

Yep.... the 1/4 turn back thing is one of those 'scuba myths' that so many instructors teach without questioning the logic in it. Personally, I just feel that it's modern use stems from a desire by dive shops to prevent heavy-handed customers from inducing over-zealous wear-and-tear on the valves.

I also teach fully-open or fully-closed. It's a good accident/incident prevention measure and, to this date, I've yet to enounter any issues with the valve seizing/sticking open etc (as I've heard claimed by some scuba pros, can be a 'common' problem necessitating the 1/4 turn back lunacy).

The scuba industry is full of persistant, but unquestioned, nonsense. A greater degree of common sense by the 'professionals' should weed these out, but sadly, they are often the culprits in peddling this unquestioned twaddle.

 

[waynne fowler]

. Unless they teach management in engineering classes nowadays?

nice!