Apeks O/balanced with G250?

[buddhasummer]

So I guess, my obsessing aside, I was at least in the right ball park.

 

[Couv]

Option D: first of all, quit worrying about little minor details and go diving… Just kidding (in part).

We all know that ain't going to happen, even though that is probably the best answer so:

B) Do nothing and just use adjuster if/when required.

My vote is start here. The G250 and other pneumatically balanced second stages increase/decrease the demand valve closing force as IP increases and decreases. If you're not getting satisfactory performance THEN make adjustments to the second stage orifice. This is all assuming you've started out by tuning the G250 to your choice of first stage at it's highest IP in the comfort of your home.

 

[Couv]

Who is this guy and what makes him special here in this context?

Anyone interested in learning about how regulators function would be well served by reading as many of Luis H's post as possible. I own and have read the two regulator bibles (Regulator Savvy and Scuba Regulator Maintenance and Repair) but I make a point to read any post he makes on the subject.

 

[buddhasummer]

We all know that ain't going to happen, even though that is probably the best answer so:



My vote is start here. The G250 and other pneumatically balanced second stages increase/decrease the demand valve closing force as IP increases and decreases. If you're not getting satisfactory performance THEN make adjustments to the second stage orifice. This is all assuming you've started out by tuning the G250 to your choice of first stage at it's highest IP in the comfort of your home.

You know me too well. Having said that (oops) response did have a semi profound effect, particularly the part about them not being Swiss watches. I realized I could relax a little and not get hung up trying to achieve the unachievable i.e pin point precision.

I understand why one should tune, and I do, a second stage to its highest ip but the whole overbalanced aspect threw me as the highest ip will depend on my max depth.

Anyway I ended up tuning the second stage just shy of freeflow at 145psi anticipating my max depths and then dialed the first stage back to 140. I'll use the adjuster if required but I think it should be fine where I most commonly play. Much ado about nothing. I apologize for my online anguishing. I do appreciate the patience shown. Cheers.

 

[halocline]

I don't think there's any appreciable difference in the way G250s and balanced apeks 2nd stages work. Since the apeks 2nd stages obviously work with the apeks 1st stages, why would the G250 be any different?

I could see a potential issue with an unbalanced 2nd stage, tuned very lightly, that has a strong venturi assist.

 

[Bryan@Vintage Double Hose]

I don't think there's any appreciable difference in the way G250s and balanced apeks 2nd stages work. Since the apeks 2nd stages obviously work with the apeks 1st stages, why would the G250 be any different?

I could see a potential issue with an unbalanced 2nd stage, tuned very lightly, that has a strong venturi assist.

I have been working with the above mentioned regulators for about a month now as they relate directly to a new project I'm working on and I agree 100% with your conclusion. The only variance in results is when the second spring bias adjustment on the Apeks is brought into play and most of that occurs at a cracking effort so low that most would find not stable enough to adjust their regulators to.

 

[buddhasummer]

I don't think there's any appreciable difference in the way G250s and balanced apeks 2nd stages work. Since the apeks 2nd stages obviously work with the apeks 1st stages, why would the G250 be any different?

I could see a potential issue with an unbalanced 2nd stage, tuned very lightly, that has a strong venturi assist.

I have no idea, DA posted in a thread that if a G250 was tuned just shy of freeflow you could expect a freeflow at an increase of 5psi. Given the overbalanced "feature" gives about 1.5psi per 10 meters I figure at 40m there'd be an increase of 6psi, this got the wheels turning. Being advised that regs are not precision Swiss watches kind of put it in perspective. I have one tuned at 140 and one at 145. I'll see for myself if there's any difference at 40ish meters. From what you are all saying I'm going to expect no difference.

I did read that Apeks re designed the poppet on the second stage to address the increase in ip at depth, true or not I don't know. Cheers.

Thanks for the reassurances, much appreciated.

 

[buddhasummer]

A little knowledge is dangerous.

 

[Bryan@Vintage Double Hose]

This may be opening a whole new can of worms for you and or you may have already taken it into consideration I don't know. When you are setting the cracking effort on a regulator using a manometer alone is its only good for a general baseline number. The problem is not with the manometer as it's plenty accurate enough for scuba work. The challenge is getting a stable and consistent vacuum through the second stage to initiate flow at the same time the first stage unseats and starts the cycle. Breathing through the second stage is not accurate as the parameters cannot be consistently controlled or repeated. How quickly you inhale, how much you inhale, volume you inhale vary with each breath and I know from experience it's near impossible to read the IP gauge and manometer at the same time as numbers on both are important when determining cracking effor. By simply changing one factor (speed, volume, etc) you will get a different reading.
In reality cracking effort by the diver is good or bad depending solely on how they feel / perceive it to be.....And we all know how well science and feelings mix sometimes.
In the end, don't let all this stuff get in the way of why you are diving to begin with

 

[BoltSnap]

This may be opening a whole new can of worms for you and or you may have already taken it into consideration I don't know. When you are setting the cracking effort on a regulator using a manometer alone is its only good for a general baseline number. The problem is not with the manometer as it's plenty accurate enough for scuba work. The challenge is getting a stable and consistent vacuum through the second stage to initiate flow at the same time the first stage unseats and starts the cycle. Breathing through the second stage is not accurate as the parameters cannot be consistently controlled or repeated. How quickly you inhale, how much you inhale, volume you inhale vary with each breath and I know from experience it's near impossible to read the IP gauge and manometer at the same time as numbers on both are important when determining cracking effor. By simply changing one factor (speed, volume, etc) you will get a different reading.
In reality cracking effort by the diver is good or bad depending solely on how they feel / perceive it to be.....And we all know how well science and feelings mix sometimes.
In the end, don't let all this stuff get in the way of why you are diving to begin with

Then how you can set it correctly per the mfg. standards without the influence of "feelings"?