Question regarding 1st stages

[tgreene]

Yesterday I had to clean a 1000g reef tank that requires diving, and I had a massive equipment failure issue to contend with... :furious:

The way in which I dive this, is to use a 25' hose that connects to an AL80 that sits on a shelf in the fish room. Yesterday however, I tried a new 1st stage coupled with my trusty old (and epoxy covered) Cressi 2nd stage, because I needed a yoke fitting for this. All of my other regs at this point are DIN. This new yoke 1st stage is also the only non dry-sealed 1st stage that I own and is the first time I've ever used one, so that may be the issue, however I doubt it.

Whenever I turn on the air, there is a very slight free-flow out of water that became MASSIVE FREE-FLOW under water. I do have an IP gauge and will be testing the IP because it seemed that it kept creeping higher and higher, though I don't know if this could have anything to do with being an open design that was operating out of water or not. I would think not, but I simply don't know.

Does anyone have any suggestions as to what I should look for other than testing and setting the IP..? I hoping to be able to use this new reg in a couple of weeks in the Caymans since it's yoke and I don't want to have to use an adapter on my DIN regs.

I guess it's always remotely possible that the problem is my 2nd stage and not the 1st, buut I highly doubt it. That would obviously be easy to test by simply attaching it to a different 1st stage, which I'll do later today.

-Tim

[SeaJayInSC]

Hey, bud! Got your phone call yesterday... Sorry I wasn't able to call you back - diving. :)

The situation that you're describing definitely isn't caused by the difference between a diaphragm and piston reg. It doesn't matter to the second stage what first stage you're using... Only that it's receiving gas that's a certain pressure.

It sounds to me like either there's something wrong with your second stage, or the IP for your first stage is set too high for your second stage.

Most second stages need 120-140 psi to function properly, so most first stages are set to deliver around 130 psi from their low pressure ports.

That's the first thing I would check... Put an IP gauge on your first stage and find out what pressure it's set to. IP "creep" will materialize as a first stage that will not maintain one, constant pressure... It constantly rises or "creeps" until it causes a freeflow. This is a problem with your first stage. If your first stage is holding constant IP (between it's correct range - you'll have to find out from Chris what the correct range is), then either there's a problem with your second stage (my suspicion) or your second stage is meant to handle much lower pressure than your first stage is set to deliver (which would cause a freeflow like you describe).

Let me know what you find - I'd be really interested in seeing what the problem is.

[tgreene]

Like I said, my guess is IP is higher than Cressi, and there may be creep as well.

-Tim

[SeaJayInSC]

Yeah, put an IP gauge on it and see what you find.

Since you already know that your Cressi's second stage requires a different IP than your first stage is delivering, likely that's the culprit. Where should each of these stages be set?

You'll know for sure once you put an IP gauge on it.

[tgreene]

It was the IP... Somehow it was at 180 and spec was supposed to be 135-140. I set it for 135, and will leave it pressurized over night to watch for any signs of creep.

-Tim

[SeaJayInSC]

Wow, yeah... That's really high. No wonder your second was freeflowing.

Is this one of your new HOG regs, or your Cressi?

[tgreene]

Wow, yeah... That's really high. No wonder your second was freeflowing.

Is this one of your new HOG regs, or your Cressi?
It was the new EDGE Yoke reg.

When I spoke w/ Chris yesterday he talked me through exactly what to do and it worked perfectly... I left it sit overnight and it's still holding perfectly without any creep, so it's good to go. :)

-Tim

[SeaJayInSC]

Yeah, I would expect that it would.

Interesting that a new reg wouldn't be adjusted properly. I've known people to say that a new set of regs often ISN'T set up properly and must be "gone through" by a tech before using... But I've never had that experience. All of my regs have always come from the factory spot-on.

Great that Chris knew exactly how to fix the issue. Easy, isn't it? Makes working on motorcycles look really, really hard. :)

[tgreene]

It's just a good thing that I had bought an IP gauge a couple of weeks ago because I knew eventually I would be needing one, and it was on sale for $20'ish at LP.

It was pretty neat to actually see how it works and even better to be able to make my own adjustments rather than paying the LDS $25 and waiting a few days to get it done. :)

-Tim

[SeaJayInSC]

Yeah, adjusting the IP on your first stage is pretty easy... And really, the only adjustment on your first.

On your Cressi second stage... Do you have both a lever and a knob, or jus the lever?

[tgreene]

Just the venturi lever that is about worthless on the Cressi reg...

[SeaJayInSC]

Lol...

Well, you know that you have a "dial" adjustment, right? It just doesn't have a knob on it.

That is... You have a cracking pressure adjustment - it's just not able to be manipulated on a dive.

To access the adjustment, remove the second stage from it's hose and look into the orifice. You'll see a slot that can be turned with a flat-bladed screwdriver. This is your cracking pressure adjustment - it's just that it has to be set and left, rather than having it be set and then "fine tuned" while on the dive (like you would if you had a knob on your reg).

Point being... Theoretically you could have solved the above problem by turning your cracking pressure adjustment waaaaay up so that the second stage would handle 180 psi. Of course, it would have breathed like a truck - it'd have been "heavy" to start breathing, and once it did, it would have delievered some serious air... Maybe even so much that it wouldn't ever stop when you stopped inhaling. :)

...But the point is that pretty much, that about covers it with regards to regulator adjustments. There's a lever height adjustment for your second stage, too, but that rarely needs adjusting and has more to do with the function of the reg and not so much the way it "feels."

From here, servicing a reg is simply about taking it apart and cleaning it up (I like to use an ultrasonic cleaner so I don't have to scrub) and putting it back together with fresh O-rings and such. It's pretty easy... Probably easier than driving it to the LDS or shipping it off to someone. :)

[tgreene]

I do know that but I don't want to play inside a reg if I don't have to, not without knowing them inside and out first...

The Cressi is the last remaining of 3 of them that I had, and it was the primary that is heavily covered in epoxy. I kept it for the sole purpose of tank diving on the Hookah rig.

-Tim