Low flow through S600

[Pearlman]

Somebody who does have the flow-vane removal tool - can you please post the length of each leg in the “L” shape? And diameter of the brass rod and rough angle of the bend (seems like 95-100 degrees)?

When I ordered a whole lot of parts from Scuba-Tools I remember consciously skipping this item and deciding I would never fiddle with the vane. But now I learnt something new today and want to reverse mine.

I found a design engineer nearby who can do this relatively simple job of crafting (or 3D printing) one - makes more sense rather than ship a $18 part for $35 International.

 

[happy-diver]

Looks like a ground bent repurposed screwdriver without the nice handle to me

 

[rhwestfall]

Plus a slot to hold the vane...

 

[Pearlman]

Plus a slot to hold the vane...

Thanks for the reminder …

 

[Bloody Knuckles]

Connect your inline adjuster and pressurize the system. It will again leak. Screw in the orifice until it just seals.
Is the lever at or below the rim of the case? Did the lever drop before it sealed? In either case, your orifice knife edge is likely scuffed (assuming you're using a new seat). If you're trying all this with the old seat, all bets are off for reasons that are multi-factorial. It might work; it might not.

@landlockeddivingdoc,

Rob commented on the seat being utilized (copied above)... I don't believe you mentioned if the seat was swapped out, but as an aside, I chased my tail for some time trying to use a "new" Trident seat. For whatever reason it just breathed like a pig with that seat no matter what I did. I eventually got my hands on an OEM Scubapro kit and voila, problem solved. Anyway, just a thought... I've found one of the toughest aspects of the DIY approach is getting the OEM replacement parts. I've gone down the "after market" rabbit hole several times with little to no success. It may take a little patience and usually a bit more $$$ to procure the OEM kits but well worth it in the long run. At least from my experience anyway. Good luck

 

[axxel57]

Thanks for the clarification. I thought that's what you meant, but I wanted to make sure.

Doing the recommended test, there was NOT an appreciable drop in the lever when I sealed between the "breath seal" and 135psi levels (I've attached before/after pictures...parallax being what it is, they aren't useful to confirm that I didn't see a drop while watching during the adjustment, but perhaps it shows that the lever remained above the case rim). As expected, there was a bit of a leak when the diaphragm and faceplate were reinstalled. After readjustment plus 5minute's rotation, cracking pressure was 1.1. The feeling of reduced flow with normal breathing persists, but notably I didn't appreciate the "diaphragm smacking" on inhalation this time.

To me this ‘reduced flow’ story sounds quite strange. If the lever is high, the orifice-poppet separation should be working at max, so the max of air flow should be triggered.

If really there is still a reduced flow, I’d check the 1st.

Is the filter or LP hose clogged?

Is the 1st stage valve working properly etc.?

But I think there is another possibility.

The feeling of reduced air flow can be easily mixed up with a higher WOB, caused by the ‘usual suspects’.

So I would inspect the lever, checking that the ‘feet’ are really parallel and it can move freely.

The 2nd looks quite old and well used and the barrel is of plastic, so I would also inspect the square holes if they are not ‘worn out’ or somehow ‘obstructed’, so the lever movement is not smooth and free.

I also would polish the plate on the membrane, which after years of use can be scratched, inhibiting the easy lever movement on the plastic plate.

A look on the S-Wing poppet to see that there is no fabrication ‘error’, checking that the contact area of the lever is as it is supposed, so the lever touches with both ‘legs’ the poppet, is another possibility.

In short, I have problems to believe that there is really a ‘reduced flow’ on part of the 2nd stage which could be checked properly anyway only on a Flow Bench.

I would suspect but a higher ‘inhaling resistance’ (IR) during flow, while inhaling.

People tend to underestimate the possibility of higher IR during a full breath because of the different factors as mentioned. They think that automatically the cracking effort (CE) should be the same as the IR.

But there are or have been 2nds on the market, which one could easily adjust to 0,7-0,8 inch h2o CE, which are breathing nonetheless pretty lousy.

If, as Rob mentioned, also the Venturi doesn’t work proper, the higher WOB could be identified as ‘reduced flow’ I think.

Anyway, maybe it would be a good idea to send the unit to Rob to make a proper check.

After that we would probably know exact what caused this ‘reduced air flow’……

Good luck!

 

[landlockeddivingdoc]

To me this ‘reduced flow’ story sounds quite strange. If the lever is high, the orifice-poppet separation should be working at max, so the max of air flow should be triggered.

If really there is still a reduced flow, I’d check the 1st.

Is the filter or LP hose clogged?

Is the 1st stage valve working properly etc.?

But I think there is another possibility.

The feeling of reduced air flow can be easily mixed up with a higher WOB, caused by the ‘usual suspects’.

So I would inspect the lever, checking that the ‘feet’ are really parallel and it can move freely.

The 2nd looks quite old and well used and the barrel is of plastic, so I would also inspect the square holes if they are not ‘worn out’ or somehow ‘obstructed’, so the lever movement is not smooth and free.

I also would polish the plate on the membrane, which after years of use can be scratched, inhibiting the easy lever movement on the plastic plate.

A look on the S-Wing poppet to see that there is no fabrication ‘error’, checking that the contact area of the lever is as it is supposed, so the lever touches with both ‘legs’ the poppet, is another possibility.

In short, I have problems to believe that there is really a ‘reduced flow’ on part of the 2nd stage which could be checked properly anyway only on a Flow Bench.

I would suspect but a higher ‘inhaling resistance’ (IR) during flow, while inhaling.

People tend to underestimate the possibility of higher IR during a full breath because of the different factors as mentioned. They think that automatically the cracking effort (CE) should be the same as the IR.

But there are or have been 2nds on the market, which one could easily adjust to 0,7-0,8 inch h2o CE, which are breathing nonetheless pretty lousy.

If, as Rob mentioned, also the Venturi doesn’t work proper, the higher WOB could be identified as ‘reduced flow’ I think.

Anyway, maybe it would be a good idea to send the unit to Rob to make a proper check.

After that we would probably know exact what caused this ‘reduced air flow’……

Good luck!

Agree with all your points.
I'm pretty sure it's not the 1st or hose since everything seems normal when the G260 is swapped out into the setup (and three s600 is still lousy when connected with a known good 1st).

Part of me thinks it's still in my head/confirmation bias since I was asked to approach it as a "hard breather," but like you said, Id have to hook it up to a flow meter to confirm.

I'm LEANING towards the Venturi giving me an increased IR despite a decent cracking effort, BUT I'm going to do those checks you recommended. Replacing a the barrel with the metal one has been on my "to do" list; the fact that it's plastic would be consistent with a reg that was made, when, in the early twenty teens? (And with the commensurate wear). Moreover, even if the cracking effort is where I want it, I find it interesting that 1.0/1.1 is also as low as it'll go- as you pointed out, a lot of (most?) modern seconds should be able to go lower-- when experimenting with my other three SP regs and couple of diverites, I was able to take them down into the 0.7x range, even though I didn't leave them there. The reference IP range in the manual is 1.0 to 1.4, so it seems like I SHOULD be able to turn it down more (and thus perhaps suggests something mechanical is still going on).

Will keep everyone updated!

 

[halocline]

What happens when you adjust it to around 1” of water, set the Venturi vane on max, and then depress the purge? Does it start a free flow? It should.

If the lever height is correct and the Venturi vane is correct, and it’s the right diaphragm and the spring is in good shape (I would replace the spring, I do that every so often on my balanced/adjustables/G250 and it makes tuning the reg easier) then I’m out of ideas, although axxel’s idea about the lever feet getting hung up on the barrel is good.

I don’t generally work on S600s so I’m not sure if I’ll be any help, but isn’t there something about adjusting the balance chamber from the opposite side as opposed to simply adjusting the orifice position?

I will say this much, I notice some variance in performance from one balanced/adjustable (or G250) to the next, and it’s usually about getting ideal lever height, which means experimenting with different levers. I have a metal ruler I use to measure the exact lever height and I’ve found that even 1 mm or less in lever height can have a noticeable effect on the performance. The situation is always along the lines of this: I use the inline adjuster to barely stop the leak, with no diaphragm in place. I measure the lever height. I put a diaphragm in, and then if I have to drop the lever any significant amount to account for the diaphragm, it’s not going to breath as well. You could start with that approach, I suppose.

 

[landlockeddivingdoc]

Time to bump the thread with an update!

So I delayed repairing this for quite a while. I was out of the country for several weeks, and then just catching up on "important" stuff when I got back. Still got to dive a couple of times, but left this particular reg on the workbench.

Anyhow, I ordered a flow vane removal tool (more on that in a bit), as well as a metal barrel upgrade. I'm putting the latter in tomorrow, but went ahead and did the vane exchange first (started a couple of weeks ago, but got delayed due to a reason which will become apparent), in accordance with the absolutely phenomenal observations by rsingler, in order to test that independently of any other upgrades.

TLDR: I really think that was it.

After my last post, i went ahead and orderd a TUSA flow vane tool, which was listed as being compatible with the S600 (as family brand with scubapro). Wasn't terribly expensive at about $15USD, and was also very easy to use: guide the slot of the tool around the vane (a strong light comes in very handy here), and then lever it against the mouthpiece molding.

... SUCCESS! (it did take a bit more force than I anticipated).

...But also drats and curses!

(If you look really closely at the left leg of the vane, you'll see that it separated).
In all fairness to my "using more force than expected," the literature did state that anytime you remove this, you might need to replace it.

I inspected the rest of it, as well as the seat, and everything looked ok except for some salt crystals beneath the o-ring (I don't know that this has ever been pulled, so that just might be a consequence of not being "deep cleaned" for many years). I cleaned the seat and ordered a replacement vane assembly.

Installation in the "maximum viva" orientation was pretty simple--the biggest problem was that the distal hinge part of the vane was hard to align--the retaining of the vane is due to deformation of the stem near the knob, so until that slid through, there was a lot of play. I put a little christolube on the assembly just to try to "smooth" the insertion, but I don't think it made a difference--once that retaining part was in, the hing portion still wasn't seated in the hole, but because the base compresses a little bit, it didn't break and i twas an easy task to guide it in. Also, one thing that I found interesting was that the arrow for the "dive/predive" indicator was printed on both sides of the valve, for (I presume) those of us who want to switch it around. I just thought that was interesting in the greater consideration of switching it.

 

[landlockeddivingdoc]

update, continued...

Anyway, after putting the new vane in, I thought it was time to test it.

I unfortunately couldn't find a second set of hands to photograph the magnahelic testing, but the cracking pressure was (as expected) essentially unchanged. But the breathing resistance did seem to be MUCH improved.

I concede that might have been due to bias and couldn't really be proved without a flowmeter, but I also had my fiance test it. her response was "There's nothing wrong with it...wait a minute, is this the one that gave you trouble all summer?"
So I'll take that as a win.

I wouldn't have thought that the vane orientation would've made that big of a difference. And maybe it doesn't...but if it doesn't, why is it in the service manual as a recommendation? But if it were that important, why not make a bigger deal about it?

So initial impressions are positive, but I'll post an update after putting it through its paces this weekend at the spring. I do, however, really think that this option should've had more publicity--or even been made standard (if someone is shelling out the money for this they really should get everything as tuned as possible...schools can get the R195/Mk2 combos if they want a "bulletproof but iffy breather."...or get the tuned S600s and really talk them up in their sales pitch.

Anyway, would certainly recommend this based on an n=1. Just be aware that you will likely (unexpectedly) have to replace the vane, which is more expensive than the tool.

(regarding the tool, i tried the long pliers thing and it didn't work, so I went ahead and bought the real thing. There were a couple of contributors that suggested making your own from a cutoff screwdriver or steel round stock...if someone was mechanically inclined, they probably could, but in the next post I'll show you why that might be a little difficult)