regulator with side exhaust vent?

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I have always liked the concept of side exhaust but wasn't really happy with my Oceanic Omega II (about 1994) and was discouraged from Poseidons by the apparent difficulty of getting a good service and tune! The new Hollis 500SE is a side exhaust with a longer exhaust shroud that should put bubbles further away from the face, I am taking a leap of faith and picking one up in a few days. Unfortunately the first ocean dive won't be until probably mid October, but I will be immediately plummeting to the 15ft depth of the dive shop pool to check it out and if anyone is interested I can post my impressions?


Have you dove your 500SE yet? Looking at them and was wondering how they performed?
 
Not yet, it breathes well dry- about as well as any decent second stage out of the water! Leaving to Cozumel next Saturday so should get 10 dives on it and then we'll see!
I normally put Jax or Seacure mouthpieces on my regs but this one has a large (wider than my other regs) mouthpiece and what looks like a larger than normal orifice.
I am wondering if it may require something like the size 5 Seacure made originally for the Poseidons?
 
Bubbles, what bubbles, I do not see any stink'n bubbles:

IMG_1443.jpg


But, frankly, this is why you have bubbles in your face, trust me, once you actually begin diving instead of kneeling on the bottom PadI style, the bubble problem will go away, mostly:

IMG_1312.jpg


Ignore my pasty white skin, but the Tekna T2100 is the greatest side breather of all time, and the worst, depending upon your perspective:

IMG_0507.jpg


N
 
…Ignore my pasty white skin, but the Tekna T2100 is the greatest side breather of all time, and the worst, depending upon your perspective…

I saw some tests from early breathing machines that showed that the Oceanic Omega was significantly improved over the Tekna — more so on the exhaust side but better on inhalation too. The simplicity of both are elegant and way ahead of their time.

I definitely like the mechanics of the Omega better. BTW, the Omega is being re-release as the Omega III but the guts of the second stage are literally the same and interchangeable with the Omega I and II. The Hollis version is released and is also internally the same.

hollisSEsmallpic.png
 
I saw some tests from early breathing machines that showed that the Oceanic Omega was significantly improved over the Tekna — more so on the exhaust side but better on inhalation too. The simplicity of both are elegant and way ahead of their time.

I definitely like the mechanics of the Omega better. BTW, the Omega is being re-release as the Omega III but the guts of the second stage are literally the same and interchangeable with the Omega I and II. The Hollis version is released and is also internally the same.

View attachment 169815

The Teknas varied significantly over the years from the metal T2100 to the T2100B an the final all plastic version the T2100B II, if I recall the nomenclature. I have had both the Omega and the Omega II. They belonged to my wife and were her main set for many years. I would not agree they breath better than the Tekna T2100. They were much wetter breathing for one and the inhalation was similar but did not come on as strong, which as I said, the Tekna may have been both the best and worst side breather of all time.

I am pretty sure that by the time the original Omega came out the T2100 had already gone to the plastic body T2100B and by the time the Omega II had come out the Tekna was no more. So, whatever tests were done, not sure it was head to head against a good T2100.

As to the new Omega III, if it looks like that, I will pass. Too much plastic, not into the organic look. Is it still a pilot valve regulator? You say the guts are the same, hmmm, interesting, if that is so.

N
 
I concur, I'm not too fond of the second stage housing on the Hollis version either but that is primarily aesthetics. Here is an image of the Omega III that is supposed to be released soon:

omega.blk__41186.1363988358.1280.1280.jpg

As for a wet breather, I find it the same as all side exhausts including Poseidon, AGA, and the few Teknas I have used. I am just trying to understand your comment since you are an experienced side-exhaust diver and I have always respected your posts.

Part of my predive trip tests has always been to suck on the mouthpiece with the first stage capped to verify the exhaust valve and diaphragm seating. I have never perceived any leakage on any side exhausts that I can remember. Like all regulators, water leaks in past your lips and blows out the exhaust. As you know, side exhausts require the exhaust to be level or tilting down for the water to exit. Aside from technique, I don’t understand how there is any difference in wetness.

Sort of thinking aloud here: Whenever I notice a little wetness in any regulator with a mouthpiece (as opposed to a hat or mask), I tighten my lips around the mouthpiece and it stops. I am guilty of holding the mouthpiece very loosely though. I often notice gas blowing out past my lips regardless of regulator design. No doubt water is entering with such a lazy grasp on the mouthpiece.

The internal ports on the Omega’s main servo-activated valve are a radial series of holes near the mouthpiece so the only way water can be picked up by the gas stream is if there is a lot of water in there and the exhaust is a higher than the inlet (so water can pool around the ports). There is an initial high-flow blast of gas on servos as that large main valve opens that might be more likely to pick up water if it isn’t dry near the ports. I like the slight sense of being inflated at the beginning of inhalation, but it can be disconcerting if you aren’t used to it though.

The biggest downside of what I consider to be an exceptionally simple and elegant design is the tiny ports in the servo valve system. It is a non-issue for Scuba but would be a problem in surface supplied where the air stream is not nearly so particle free. Since the hole through the valve diaphragm in the main valve is so tiny and feeds the larger servo valve, a particle-clog will cause wide-open free-flow. The advantage for surface supplied is the second stage breathes easily with a broad range of inlet pressure. I doubt they ever tested it beyond normal IP ranges, that is just an uncalibrated personal estimate. I have used it with 80-175 PSI over bottom pressure and didn’t detect increased resistance or leakage.

I did zero maintenance to an Omega second stage for 27 years as a test, beyond rinsing in fresh water. There is only one, albeit tiny, spring where calibration isn’t very critical. There are basically only two moving parts, the servo valve lever (with spring) and the deflecting main valve rubber disk or diaphragm. I am not sure that tests on an ANSI breathing machine were ever done on the Tekna so it is hard for me to make any quantitative comparisons.

Do you have any thoughts on what could make the Omega feel like a wetter breather than the Tekna?
 
Do you have any thoughts on what could make the Omega feel like a wetter breather than the Tekna?

Both of ours leaked. The leak was through the combo exhaust valve diaphragm. My wife constantly complained. The Teknas, every one I have ever had were dry, the Omega always felt like I was inhaling a water mist. The Omega II was returned for service and the wet breathing, came back worse.

As far as needing service, neither of the Omegas are any of my Teknas ever really needed service and indeed it was said the T2100 was intended never to need service in normal use. This turned out not to be entirely true. The little tilt valve seat would go bad and it is a weakness for sure.

I also think there was perhaps dead space in the Omega, that collected water and recycled it into the mouthpiece and this dead space did not purge when exhaling, especially left side up.

As to the Omega breathing, inhalation, it felt detuned compared to a T2100. I think the leakage was through the exhaust valve/diagram and was worsened by my wife's tendency to sometimes swim slightly left side up. Hopefully the new version will have an improvement there. I hope it is successful but I will not be purchasing one, like I said, too much plastic and fluffy exterior design. The original Tekna and Omega excited me because of their minimalist design and tiny size. And the servo valve design.

Had it not been for the leaking and wet breathing, my wife would still be using the Omegas. They did not exhibit the surging and stutter and general jumpiness of the T2100 and the T2100B in shallow water (<30 feet).

N
 
Quote: "Both of ours leaked. The leak was through the combo exhaust valve diaphragm. My wife constantly complained. The Teknas, every one I have ever had were dry, the Omega always felt like I was inhaling a water mist. The Omega II was returned for service and the wet breathing, came back worse."

I had the same experience with my Omega, I really wanted to like mine but after 6 or 8 gurgling dives got rid of it.
The new Hollis 500SE eliminates the combined diaphragm/ exhaust valve and instead places the separate exhaust valve in front and to the side (diving in the ideal horizontal forward facing position the exhaust valve will be oriented much like a typical second stage- except facing rearwards, I think!?) I am optimistic about this reg and will post my impressions after a few days of diving next week.
Incidentally, I can now confirm that the mouthpiece is the same size as the Poseidon and fits a Type 5 Seacure very nicely with no leaks on sealed inhalation.
 
Both of ours leaked. The leak was through the combo exhaust valve diaphragm. My wife constantly complained. The Teknas, every one I have ever had were dry, the Omega always felt like I was inhaling a water mist. The Omega II was returned for service and the wet breathing, came back worse&#8230;

&#8230;I had the same experience with my Omega, I really wanted to like mine but after 6 or 8 gurgling dives got rid of it.
The new Hollis 500SE eliminates the combined diaphragm/ exhaust valve and instead places the separate exhaust valve in front and to the side (diving in the ideal horizontal forward facing position the exhaust valve will be oriented much like a typical second stage- except facing rearwards, I think!?)&#8230;

Interesting. I&#8217;m pretty sure that all the Omegas I have used thus far have been the first version. The Omega II &#8220;appeared&#8221; to have identical housings and diaphragm/mushroom valves as the first version.

Did either of you try pulling a suction on the second stage with the first stage plugged to see if you could locate the leak? Of course it is no guarantee that this trick works on low differential pressure leaks. I can&#8217;t think of any reasons that a mushroom valve would perform differently mounted in a diaphragm or solidly in a housing???

They sold a lot of these and a lot of divers still love them so I wonder if it could have been as simple as bad batches of parts from the molder that didn&#8217;t get discovered in QA? It is a much larger mushroom valve than most, I wonder if that was a factor?
 
Interesting. I’m pretty sure that all the Omegas I have used thus far have been the first version. The Omega II “appeared” to have identical housings and diaphragm/mushroom valves as the first version.

Did either of you try pulling a suction on the second stage with the first stage plugged to see if you could locate the leak? Of course it is no guarantee that this trick works on low differential pressure leaks. I can’t think of any reasons that a mushroom valve would perform differently mounted in a diaphragm or solidly in a housing???

They sold a lot of these and a lot of divers still love them so I wonder if it could have been as simple as bad batches of parts from the molder that didn’t get discovered in QA? It is a much larger mushroom valve than most, I wonder if that was a factor?

I don't think I tried that- it was probably 15 years ago so I can remember for sure, I know I had it checked out by a shop and they said it was working OK?
 
https://www.shearwater.com/products/swift/

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