Unavoidable flow in Halcyon Halo (SP G250V) 2nd stage

[estresao]

Hi everyone,

Sometime ago I had some issues with the crancking effort of my Halcyon
Haño 2ns stage, which happens to be the same "animal" than the Scubapro G250V. I were able fix the issue and learned a lot from the people in this forum. All is accesible on this post.

But.... life goes on, fishes grow up, my age trend to match my phone number.... and my bloody Halcyon Halos keep going anoying me.

This time is another case of weird issue. In short, I'm able to adjust the 2nd like perfect, 1 water inch cranking effort, no flow, etc, etc... but.... but... I go dive and, litle by litle it start exausting a litle flow of air continously which, if I remove the reg from my mouth, it can become bigger. I only can manage closing the "wheel" but, to stop the flow rhe cracking effort becomes too hard (once I sufaced with some headache).

I've tunned it many times, used different lubricants, applied the lubricant in different ways unsuccessful.

I guess the problem could be some sort of xhange in the spring or the lever. That's happening to me on both regulators, which are both exactly the same model.

Is anyone familiar with this issue?

Thanks!

 

[lexvil]

Check the IP, possibly a first stage issue.

 

[estresao]

Check the IP, possibly a first stage issue.

Good point!

This is very interesting.... my system is double tank an both behave very similar conected to a 220bars tank.

After opening, when I connect the intermediate pressure gauge, it start at 10bars and increases slowly until they reach 11bars.

I have to review my notes, but I think ai've set then to 9bars. It seems I made same mistake on both.

 

[estresao]

I've read somewhere a Scubapro web oage where they say the intermediate presure should be (psi/bar): 133-142/9.2-9.8.

That means mine is 1bar above.. could that be the reason of my issue?

It's normal it start at 10bars and increases little by little up to 11bars?

Meantime I'll adjust the pressure to the recommended one.

 

[sea_ledford]

I've read somewhere a Scubapro web oage where they say the intermediate presure should be (psi/bar): 133-142/9.2-9.8.

That means mine is 1bar above.. could that be the reason of my issue?

It's normal it start at 10bars and increases little by little up to 11bars?

Meantime I'll adjust the pressure to the recommended one.

Yes, that can certainly be the problem. Full service of the first stages should fix the issue. You are getting air leaking from the high pressure side to the intermediate pressure side, causing the second stages to flow.

 

[estresao]

Yes, that can certainly be the problem. Full service of the first stages should fix the issue. You are getting air leaking from the high pressure side to the intermediate pressure side, causing the second stages to flow.

I've readjusted them and now they range from around 9 to 10 bars, which is OK according to Scubapro. On of them ranges a little wider than the other, so I've adjusted from almost 9 to 10.

In few I'll service both first stages and will check if is there any notch in the valve, but I don't think, because once they reach a pressure they don't move any more.

 

[L13]

In few I'll service both first stages and will check if is there any notch in the valve, but I don't think, because once they reach a pressure they don't move any more.

That sounds more like o-rings sticking rather than sliding. A clean and rebuild with new lubricated o-rings should fix it.

 

[Nemrod]

The Mark 20/25 have, IMO, a rather soft lockup for lack of better description. If your IP is outside the specification, high side, you could have difficulty as described with your regulator second stage leaking during use.

A balanced piston first stage will usually have a small IP increase after the seat takes a set. That may be why your IP has crept up from your original setting back a few months. Or, are you saying the IP creeps up in use?

Out of curiosity, what orifice is in your second stages? Nylon, stainless, brass, gold? I have the best luck really with the (current) white Nylon SP orifice. Are they aftermarket orifice?

 

[estresao]

What I've just learned, which I think leaded me to this issue, is that when you open the tank the IP quickly reach a point where the pressure start increasing very slowly and take a little to do the approximately last bar.

This fact is important because I was unaware of this and was thinking once you open the tank immediately the IP reached the final pressure so, with that in mind, I was committing a chain of errors when fine tuning my regs:

- I was interpreting Scubapro recommendation "intermediate pressure should be (psi/bar): 133-142/9.2-9.8." as a range where you should set your IP, so I chosen the top pressure, 9.8 bars.
- 1st stage was tuned to reach near near 10 bars before the last bar increment, so after a little time, it reaches something near 11 bars... too much!
- 2nd stages were tuned to the point of almost free-flowing without waiting to reach the top IP so, after a little while, my regs started flowing easily.

What I will do (when I have some spare time are the following):
- Fine tune the 1st stage so that the top IP doesn't go beyond 9.8 bars (already done).
- Leave regs mounted with tanks opened for a long period of time to discard 1st stage leakage and ensure the top IP never goes beyond 9.8 bars.
- Fine tune 2nd stages giving time to reach the top IP pressure.

Regarding of the Scubapro recommendation of "intermediate pressure should be (psi/bar): 133-142/9.2-9.8.", I guess this range is the one where the final IP should be within, not the range for the "last bar increment".

An regarding the "last bar increment", it's interesting see that, because my gear is a DIR style double tank, one 1st stage have a little wider "last bar increment".... actually a little more than a bar. I was wondering which factors could impact on this, like 1st stage springs, or LP pressure hose status.

 

[estresao]

I've found this interesting article clarifying some stuffs I have not considered.