Regulators will flood when upside down?

[halocline]

Went diving yesterday and my primary second stage still flooded. My new Zenith secondary second stage did not (maybe me memory for the primary dives are a bit fuzzy)

Did the test you described above and was able to draw air in my recently serviced second stage. I'll take it into the shop and have them fix it.

That probably means there's a problem with the 2nd stage. Occasionally there are 2nd stages that have a seat-saver feature that keeps the valve open when it's not pressurized. If your alternate has that feature, the vacuum test won't work because air gets in the alternate, flows up the hose to the first stage, then out to the 2nd stage that you're testing. Usually when I get some air on a vacuum test of a 2nd stage, I'll then take it off the 1st stage, put my thumb over the inlet fitting, and try again. This isolates the 2nd stage completely and you know for a fact that if you get any air, it means a leaky 2nd stage. You could try that if you want to; it's pretty easy to take the 2nd stage off at the first stage, then just cover up the hose end with your thumb. Any leak in the hose would have resulted in a monster stream of bubbles while you diving, so you can eliminate that.

 

[axxel57]

Went diving yesterday and my primary second stage still flooded. My new Zenith secondary second stage did not (maybe me memory for the primary dives are a bit fuzzy)

Did the test you described above and was able to draw air in my recently serviced second stage. I'll take it into the shop and have them fix it.

For me that sounds like during service the technician did not pull the new exhaust valve nipple completely through the orifice so the exhaust valve is not perfectly flat on the surface ( or there is some dirt on the surface).

If you can,have a look into 2nd and check if the exhaust valve is in the correct position.

You can adjust the TITAN LX very light also, well below the 1,0 inch/h2O, this could add to wet breathing in an inverted position because, but it would not explain flooding.

 

[HungoverDiver]

So I took them into the shop today, and look what was found!


Something (bugs?) ate some of the silicone off my exhaust diaphragm. This is most likely the problem. Kind of surprising since it was just serviced and they couldn't think of a bug in San Diego that would do this. Maybe in the tropics but not here.

 

[halocline]

Several factor affect how the mushroom valve open: geometry, position, valve stiffens, and pressure differential will all affect the exhaust valve behavior.

A vertical valve will open wider at the top than a horizontal valve (I have observed it during several experiments). The air bubble will form at the top edge and open the valve (wider). When that occurs, a little bit of water will leak just below the bubble, on the open valve edge. Note: the stiffness of the valve will affect the shape of the open valve, as in how much of the edge is lifted.

Other geometry conditions that will affect any water back-leak. For example: if there is any lip holding an air bubble just outside of the exhaust valve (in the swimming position) the regulator may be a bit dryer in the swimming position.

When the valve is in the lowest point, you also purge any moisture on every exhalation so it doesn't build up.

The pressure differential would also affect how the mushroom valve open a bit, but I haven't actually tested or observed this effect close enough to make any definitive conclusions.

The bottom line is that position does mater, but how much will depend on several factors.

One thing I can see is if the valve is underneath a hard surface (like in horizontal face down diver position) the air bubble exiting the exhaust valve could keep things a little drier due to surface tension; it's sort-of held in place for a small amount of time as it clings to the bottom of the regulator case. When the valve is above the hard sealing surface, the buoyant air bubbles would rise up immediately away from the hard surface allowing for water to get in easier....that's a guess now that I'm thinking about it.

But I still think by far the biggest issue is that any water that gets past the exhaust valve simply drains out on the next breath in face down position, where as when you're looking up, that water drains into your mouth. This is also true with any water that drains into the reg via small gaps in the mouthpiece sealing against your lips.

---------- Post added June 4th, 2014 at 01:42 PM ----------

So I took them into the shop today, and look what was found!

View attachment 185968
Something (bugs?) ate some of the silicone off my exhaust diaphragm. This is most likely the problem. Kind of surprising since it was just serviced and they couldn't think of a bug in San Diego that would do this. Maybe in the tropics but not here.

Looks like the technician didn't bother to even check the exhaust valve or do a vacuum test. Just another example of why I service my own gear.

Anyhow, I'm sure this exhaust valve was leaking plenty in normal face-down diving position, it's just that you drained it with each exhalation.

 

[Tony387]

Yeah, it's amazing what a cursory inspection of a regulator will turn up. I would look for another LDS.
Glad you got it figured out.

 

[axxel57]

So I took them into the shop today, and look what was found!

View attachment 185968
Something (bugs?) ate some of the silicone off my exhaust diaphragm. This is most likely the problem. Kind of surprising since it was just serviced and they couldn't think of a bug in San Diego that would do this. Maybe in the tropics but not here.

Well, that's beyond my imagination that someone did not check the exhaust valve while conducting the service.

It means also the vacuum test was not done. Pretty lousy job.

Just learn to do it yourself, you will find lots of support here in the forum.

 

[HungoverDiver]

Went diving yesterday and everything is all fixed. It was the exhaust value. Thanks again everyone!

 

[LeadTurn_SD]

So I took them into the shop today, and look what was found!

View attachment 185968
Something (bugs?) ate some of the silicone off my exhaust diaphragm. This is most likely the problem. Kind of surprising since it was just serviced and they couldn't think of a bug in San Diego that would do this. Maybe in the tropics but not here.

A hungry cockroach can do that. We have monster-sized ones here. Not sure why it would chew a non-organic object, but oh well.

Went diving yesterday and everything is all fixed. It was the exhaust value. Thanks again everyone!

I'm glad you got the problem sorted out!

Best wishes.

 

[keyshunter]

Hungover,
Cockroaches live everywhere in the US, including San Diego. They really seem to have an appetite for silicone parts such as diaphragms, mouthpieces, etc. Here in the Keys we have some SERIOUS roaches. I always store my regs, masks, etc. in roach proof containers.

 

[tech_diver]

You were fortunate the cockroach was gone when you took your first breaths. Other divers have discovered the cockroach issue the hard way.