Argonaut Kraken exhaust loop flooding issue...?

[Luis H]

I don’t know what does the first stage seat has to do with the exhaust hose, or why did you posted that in this thread. In any case, I am actually seeing two different things on the pictures of that seat. The indentation from the volcano and a crack on the surface of the seat material. It is just a picture, so please let me know If what I see from the picture is not correct.

I am pointing to the indentation from the volcano orifice with a red arrow and to the crack with a green arrow.

I also added a red circle on top of the indentation from the volcano orifice. You may notice that the crack doesn’t for a good circle. It doesn’t even has a smooth curve.

This crack is definitely a defect or a malfunction. Again I do not know where Bryan gets his seats other that they are being made by a Scuba parts manufacturer/ supplier. I have seen bad seats before.

The red circle is covering volcano orifice indentation:

If you are unhappy with your Argonaut, you should contact Bryan. He will probably give your money back, but I can’t speak for him.

 

[Couv]

New o-rings in the DSV, new exhaust valve in the Kraken can, wagon wheel valves OK, hoses all in near-new condition, clamps tight. The exhaust loop STILL floods randomly in specific conditions... !

Perhaps I missed it, sorry if I'm asking you to repeat yourself. When you sent the AK back to Bryan, did you mention the exhaust hose flooding? Has the exhaust valve been replaced? I think Luis' idea of beefing up the valve stem with sealant which adds more tension to the skirt is worth trying. If the mushroom valve has been replaced, try to determine if the there is a defect with the spider.

 

[Fibonacci]

I don’t know what does the first stage seat has to do with the exhaust hose, or why did you posted that in this thread. In any case, I am actually seeing two different things on the pictures of that seat. The indentation from the volcano and a crack on the surface of the seat material. It is just a picture, so please let me know If what I see from the picture is not correct.

I am pointing to the indentation from the volcano orifice with a red arrow and to the crack with a green arrow.

I also added a red circle on top of the indentation from the volcano orifice. You may notice that the crack doesn’t for a good circle. It doesn’t even has a smooth curve.

This crack is definitely a defect or a malfunction. Again I do not know where Bryan gets his seats other that they are being made by a Scuba parts manufacturer/ supplier. I have seen bad seats before.

The red circle is covering volcano orifice indentation:

If you are unhappy with your Argonaut, you should contact Bryan. He will probably give your money back, but I can’t speak for him.

Luis, thanks for your detailed reply... much appreciated.
I included the HP seat issue because it was the original problem I was having with my near-new Kraken and the reason I returned it to Bryan.
The HP seat failed on the first dive of Day 3 on a 9 Day trip having worked fine up till then... it was venting air until the IP spiked to about 200psi and the octo started purging.
I originally thought the HP seat blow-by could have had some influence on the exhaust loop.
It probably needs a separate thread for clarity:
Argonaut Kraken HP seat failure...?

 

[Fibonacci]

Perhaps I missed it, sorry if I'm asking you to repeat yourself. When you sent the AK back to Bryan, did you mention the exhaust hose flooding? Has the exhaust valve been replaced? I think Luis' idea of beefing up the valve stem with sealant which adds more tension to the skirt is worth trying. If the mushroom valve has been replaced, try to determine if the there is a defect with the spider.

Yes I specifically asked Bryan in two separate emails whether he or Luis had experienced the exhaust loop flooding issue .
No reply, but he did mention in another thread he had spent a lot of time recently dealing with new Kraken owners re a 'hard breathing' problem. Maybe related to the exhaust hose flooding problem... it was certainly very disconcerting when it happened unexpectedly and WOB went through the roof!
The exhaust valve was replaced.
I will recheck the spider, it's possible it is slightly distorted (common in an injection moulding going from a very thick wall section to one much thinner).

 

[Couv]

The exhaust valve was replaced.
I will recheck the spider, it's possible it is slightly distorted (common in an injection moulding going from a very thick wall section to one much thinner).

Incidentally, if you had a massive freeflow for an extend period of time, I do think it could have affected the exhaust valve in a negative way (again, time to apply a little Luis Magic to the stem.) However, if it's been replaced since then and the problem returned something else is amiss.

I'm looking forward to your update on the condition of the spider.

 

[TectonicDrake]

Thanks Luis! I appreciate your recommendations on what to look for with the exhaust valve and the trick with the silicon sealant. I will search for small debris and also look with the light. I love my kraken, I'm just needing help sorting out the proper care and feeding related with being a first time double hose owner.

 

[Fibonacci]

A flooded hose will happen if the valve is not sealing well. The valve has to be only stiff enough to hold their shape. They are not intended or designed to hold back any pressure. They just have to hold their shape and keep contact with the sealing surface.

I already suggested to put a drop of silicone seal/glue under the arrow head in the stem to make sure the valve center is held tight against the spider support. I have seen mouthpiece valves were the stem is a just a bit long, the valve is a bit loose, and they leak. If the center of the valve is not tight against the spider, the edge may not make good contact with the sealing surface.

~snip~

Adding stiffness to the valve will not improve the sealing edge contact unless the issue is an uneven or rough contact surface. The sealing surface of the can was designed to be flat and smooth to provide a good sealing surface.

~snip~

If you have had flooding, more than once, there is something wrong with the interface between your valve and your can.

You can try checking the sealing edge doing a light test. In a dark room shine a small light into the exhaust horn and see if there is any light leak around the edge of the mushroom valve.

NOW we are getting somewhere!
Did the Luis test and the valve leaks light like a sieve in a couple of places

Marked these and folded back the valve... they correspond to where a couple of the spider arms meet the housing, a sink mark or weld point as the molten resin is packed into a relatively thin wall section.
Hard to see in the photo, you have to get the light just right but there is a 'dimple' in each area, sometimes it is just localised other times it carries through to the outer wall.
So at rest on exhale, the valve would not be sealing correctly in these areas and water enters the loop!

So thanks to Luis and Couv for offering detailed advice, that appears to be the root cause of the flooding problem... but what is the robust long term fix?
Spotfacing the sealing surface in a mill?

 

[tbone1004]

@Fibonacci if you have a mill that would be ideal. If not I bet if you took a flat sanding block and took a few mils off to flatten that out it would do the trick

 

[rhwestfall]

or a new can...

 

[Luis H]

Have you tried putting a bit of silicone glue under the arrow head to hold the stem in the center tight against the spider?

The trick to put some weight that will hold the center against the spider over night so that it cures in the correct position.

I actually put a little bit of caulking under the spider before I install the valve and I put just a little bit more under the arrow head.



I have seen those in the molded piece and I am fairly sure I know why they are happening, but that is not important at this point.

It is a real shame that there is an imperfection, but the imperfection doesn’t seem to be affecting most units. I don’t know if the imperfection varies on the different cans. I don’t have a lot of experience with the tolerance changes in molded plastic parts. But I have never had an exhaust flood (I have hundreds of dives on my Argonauts) and there are hundreds of Argonauts out there that seem to be working fine.

The imperfection doesn’t have any sharp edges/ discontinuities. Therefore, even do it may not be perfectly flat, the soft conforming valve has a reasonable chance of forming a reliable seal. This is why I keep on suggesting how to install the valve to have the best chance of being properly seated.


This is not the end of this. I will be talking to Bryan about it, but in the mean time, please try what suggested.