Halcyon Halo feels like it breathes in 2 stages

[stuartv]

Hmmm, since the problem keeps coming back after a short amount of dives I wonder if its a lube issue.

To be clear with the tech I did not pay him to do a full service. It was a "quick fix" he attempted to do and it did feel like it temporary made it better. I think he also re-seated the poppet.

My personal pet theory is that there is an O-ring on the poppet somewhere that is a very slightly different spec than what ScubaPro was originally using on the G250V. Just slightly bigger OD, or maybe slightly too small ID. My theory is that, when it's first lubed and assembled, it works okay. But, as the lube wears off some, then the out-of-specness (c Copyright, me) starts to make it have stiction that results in the symptom we're all having.

Whatever. I hope H figures it out soon! I want my regs back and working correctly... so I can sell them in good conscience and be done with them. I have a new Atomic reg set for single tank that I will be using from here on out.

 

[Nemrod]

My personal pet theory is that there is an O-ring on the poppet somewhere that is a very slightly different spec than what ScubaPro was originally using on the G250V. Just slightly bigger OD, or maybe slightly too small ID. My theory is that, when it's first lubed and assembled, it works okay. But, as the lube wears off some, then the out-of-specness (c Copyright, me) starts to make it have stiction that results in the symptom we're all having.

Whatever. I hope H figures it out soon! I want my regs back and working correctly... so I can sell them in good conscience and be done with them. I have a new Atomic reg set for single tank that I will be using from here on out.

Some years back, not the Scubapro historian that some are, but they went to a dual O-ring poppet and a longer/deeper balance chamber to accomadate the additional O-ring. The purpose of the second, now outer O-ring was not a belt and suspenders to sealing the chamber and poppet but was to act as a wiper and also to seal in lubricant to prevent washing. Well then, now two O-rings must drag in the chamber, not just one, and no matter what we do, one of them, the exposed O-ring, will be washed of lubricant and exposed to fine debris, salt crystals, whatever gets in there. But, and it is a big but, if that is true, that is why they added the second O-ring then their engineering was aware of washing of lubricant. What I do not recall is was this additional O-ring added post the acceptance of or concurrent with Nitrox as a sport diving gas (because it was once called Voodoo Gas if some might recall and forbidden and highly controversial)? Where I am going with this thought is that anything O2 safe pretty much sucks as a lubricant and is more subject to washing than is good old 100% silicone grease. Just some supposing and I am probably all wrong.

I wonder also if some balance chambers are not within specification, more so than the O-rings.

 

[Kupu]

I have occasionally experienced the 2 stage breathing issue being described while rebuilding G250s. After the initial rebuild and even with adequate silicone grease on the poppet orings, the issue could be persistant. Switching and swapping poppets, balance chambers, and springs was the solution. Sometimes incorporating the old style balance chamber worked better than the new style. Nothing scientific about the process and I don't recall narrowing down the issue to a particular part.
What I don't know is whether or not the issue returned with use on these regulators, as has been mentioned several times.

Since a moderate level of variance is allowed on new OEM .216 springs when they leave the factory, it does not seem a stretch to think other poppet assembly parts can vary as well.
Possibly dumb luck, but I've not had the 2 stage breathing issue come up on personal use second stages using the Scubapro s-wing poppet setup. My process is to put a fairly heavy coat of silicone grease on the two orings and then work them thru a few cycles in the balance chamber, then relube them again before final assembly.

The switch from 1 to 2 orings on the poppet was during 1999. The attached bulletin gives a few details.

 

[Swamp_monster]

My personal pet theory is that there is an O-ring on the poppet somewhere that is a very slightly different spec than what ScubaPro was originally using on the G250V. Just slightly bigger OD, or maybe slightly too small ID. My theory is that, when it's first lubed and assembled, it works okay. But, as the lube wears off some, then the out-of-specness (c Copyright, me) starts to make it have stiction that results in the symptom we're all having.

Whatever. I hope H figures it out soon! I want my regs back and working correctly... so I can sell them in good conscience and be done with them. I have a new Atomic reg set for single tank that I will be using from here on out.

Have you told Halcyon about this theory? Sounds logical to me... When I called Halcyon the guy I talked to told me he has heard of this before in a training video but when I asked him the cause he could not recollect the exact cause and said to send it in or bring to a certified tech. I had another tech take a look at it Friday, I now have 4 dives on it since he tweaked and it seems to be breathing better however on my last dive yesterday I did notice the two stage breathing in a couple instances but not like how it was before. I will repost here if the issue returns.

 

[lexvil]

The poppet design is pretty universal, basic design, double o-ring etc. it’s more likely an interface issue maybe cause by sloppy specs.

 

[Nemrod]

Just out of curiosity, if you were to turn the VIVA control back a little bit towards the pre-Dive postion does the two stage "feature" go away or is reduced?

I am not saying there is nothing wrong, that remains to be seen, but to say it again, the G250 of all variations and the current G260 have a very aggresive Venturi and when you go from sipping to a higher demand the Venturi is going to kick in strongly on this design and I do consider it a feature of the regulator. I am not meaning to be snarky but perhaps some folks just need a different regulator that has a more progressive transition to suit their breathing pattern better.

Kind of like bifocals with a line and those with progressive lenses. I like the line, above it is nothing, below it is all in where as progressives seem to smear betwixt the two and I never know where I am until I get dizzy and fall over. Well, that is a weird corollary, but, yeah, a G250, if you pull on it then it is going to be all in! Kind of like there is a line there between a little and a lot.

 

[stuartv]

Just out of curiosity, if you were to turn the VIVA control back a little bit towards the pre-Dive postion does the two stage "feature" go away or is reduced?

I am not saying there is nothing wrong, that remains to be seen, but to say it again, the G250 of all variations and the current G260 have a very aggresive Venturi and when you go from sipping to a higher demand the Venturi is going to kick in strongly on this design and I do consider it a feature of the regulator. I am not meaning to be snarky but perhaps some folks just need a different regulator that has a more progressive transition to suit their breathing pattern better.

Kind of like bifocals with a line and those with progressive lenses. I like the line, above it is nothing, below it is all in where as progressives seem to smear betwixt the two and I never know where I am until I get dizzy and fall over. Well, that is a weird corollary, but, yeah, a G250, if you pull on it then it is going to be all in! Kind of like there is a line there between a little and a lot.

No, the venturi switch position makes no difference.

It breathes well when it's first serviced. It turns to rubbish after a few dives. After a few more dives, the transition becomes bad enough to be a very discernible "pop" sensation. Almost like the opposite of when you first exhale through a reg that has been sitting for a while and has a mushroom that has stuck to the reg body. Except it's on every inhale.

My G260s have never behaved anything remotely like this. Nor any of my other regs, of course.

I don't think it's a matter of needing a different regulator that has a more progressive transition.

I think there is something wrong with them that needs to be figured out and fixed.

 

[Swamp_monster]

No, the venturi switch position makes no difference.

It breathes well when it's first serviced. It turns to rubbish after a few dives. After a few more dives, the transition becomes bad enough to be a very discernible "pop" sensation. Almost like the opposite of when you first exhale through a reg that has been sitting for a while and has a mushroom that has stuck to the reg body. Except it's on every inhale.

My G260s have never behaved anything remotely like this. Nor any of my other regs, of course.

I don't think it's a matter of needing a different regulator that has a more progressive transition.

I think there is something wrong with them that needs to be figured out and fixed.

I will say I already had to replace the orings on the swivel spool - it started leaking after maybe 25 dives... The green orings looked like they had dry rot; if the orings inside the reg are anything like those orings on the swivel spool I could easily see that causing the issue.

 

[Nemrod]

No, the venturi switch position makes no difference.

It breathes well when it's first serviced. It turns to rubbish after a few dives. After a few more dives, the transition becomes bad enough to be a very discernible "pop" sensation. Almost like the opposite of when you first exhale through a reg that has been sitting for a while and has a mushroom that has stuck to the reg body. Except it's on every inhale.

My G260s have never behaved anything remotely like this. Nor any of my other regs, of course.

I don't think it's a matter of needing a different regulator that has a more progressive transition.

I think there is something wrong with them that needs to be figured out and fixed.

Good to know. I cannot wait to hear what Halcyon has to say.

 

[stuartv]

Good to know. I cannot wait to hear what Halcyon has to say.

That makes two of us, my friend!