SP S-650 Leaks air

[merxlin]

I have a 2 1/2 year old S-650 that developes a condion where it leaks air. Not a freeflow, just a trickle of air when the inlet side should be shut down, like between the exhale and inhale. If you pull the reg out of your mouth, it wil keep a small stream (pencil size) of bubbles running constantly. I had it serviced abuout 20 dives ago, where they said they replaced virtualy all moving parts and it was breathing about 20% better than factory spec (it did breath very nice )and it was fine. Now it has started again (for the 3rd time). I am going to ask my LDS to see if SP will replace it. (We'll see). Anyone have anything like this happen to them?

 

[Isaac-1]

It sounds like you may have a pressure leak in your 1st stage, the pressure builds up and the 2nd stage is doing its job by releasing the pressure.

 

[scubafanatic]

...agreed, sounds like a 1st-stage HP seat failing...as the IP climbs the 2nd stages vent/free-flow the excess pressure......also, I believe the 650 went through a major recall/crisis a while back...LOTS of 'issues' with the 2nd-stage, and I believe it's no longer in production...which seems to be Scubapro's admission that it wasn't a successful design.

 

[halocline]

Unless the slow free flow is on both 2nd stages, I would not suspect IP creep. The tech said it "breathed 20% better than factory spec" when he rebuilt it, which says to me that he set the 2nd stage cracking pressure very low. After the seat takes a little set, it's not uncommon for it to leak a little if it's adjusted for very low cracking pressure.

Is this an S600 or an X650? They both have user adjustable cracking effort so I assume you've tried tightening the reg down with the adjuster, correct?

Is the octo leaking as well? There is a very easy check to see if the IP is creeping; just have your shop put an IP gauge on the LP inflator hose and have a look, or spend $25 yourself and buy a gauge if you have an interest in these sorts of things.

 

[merxlin]

Unless the slow free flow is on both 2nd stages, I would not suspect IP creep. The tech said it "breathed 20% better than factory spec" when he rebuilt it, which says to me that he set the 2nd stage cracking pressure very low. After the seat takes a little set, it's not uncommon for it to leak a little if it's adjusted for very low cracking pressure.

Is this an S600 or an X650? They both have user adjustable cracking effort so I assume you've tried tightening the reg down with the adjuster, correct?

Is the octo leaking as well? There is a very easy check to see if the IP is creeping; just have your shop put an IP gauge on the LP inflator hose and have a look, or spend $25 yourself and buy a gauge if you have an interest in these sorts of things.

My bad- its an X-650. I have adjusted it and it goes from OK to worse. When I had it serviced, it went from the in house tech who couldn't fix it to an outsource lab. I was told that they basically replaced everything that moved, springs, seals, etc. It worked great for about 10-12 dives before it started up again. When it did work right it was almost like not breathing at all, very effortless.

I'll contact my LDS and see what he can do for me. Funny thing is my pre-recall reg was fantastic. The replacement I received had a bad exhaust diaphragm and never really felt as good as the original. It was also the reg I started using when first certified so I figured I was just getting a bit more sensitive to how it was working, and may not have noticed it in the original. Now there is this issue which I just lived with for 5-6 months before trying to get it repaired. I have no more confidence in this reg. Maybe they'll swap it for a G250V.

 

[Isaac-1]

Unless the slow free flow is on both 2nd stages, I would not suspect IP creep.

It is not uncommon for only one regulator to leak air with high IP, particualry if the second stages are not a matched set as their cracking effort, etc. will likely be set a bit different.

Ike

 

[halocline]

It is not uncommon for only one regulator to leak air with high IP, particualry if the second stages are not a matched set as their cracking effort, etc. will likely be set a bit different.

Ike

Yeah, but the octo, if unbalanced, is much more sensitive to changes in IP than the balanced primary. So, if it were an IP issue, I would expect the octo to leak first.

I would suspect the 2nd stage in this case, but there is a very easy test to see if the IP is creeping. If your LDS tech can't do that much, then it's definitely time to find a different tech.

What's your first stage, what's your octo, and did the tech at your LDS check the IP?

 

[merxlin]

Yeah, but the octo, if unbalanced, is much more sensitive to changes in IP than the balanced primary. So, if it were an IP issue, I would expect the octo to leak first.

I would suspect the 2nd stage in this case, but there is a very easy test to see if the IP is creeping. If your LDS tech can't do that much, then it's definitely time to find a different tech.

What's your first stage, what's your octo, and did the tech at your LDS check the IP?

1st stage is a MK-25, and I use an Air II so that is not much help. I also have a backup Octo that can freeflow if you look at it sideways. I can hook that up and see if it leaks, but last time I did use it with this 2nd stage, it did not freeflow or leak.

2nd stage and 1st stage were serviced together, and there were some issues with the 1st stage so I know the IP was checked.

I was able to borrow the LDS owners setup for some dive while mine was still in the shop, since it is the same as mine. I noticed it breathed a lot better than mine until the service was done. Then they seemed equal. I have also used his X-650 with my 1st stage without the problem.

Thanks for all the info. I'll let you know what the shop says. BTW, I've already made it clear that the in house tech does not work on my gear anymore due to some other issues.

 

[DA Aquamaster]

I own a pair of X650's. One I bought early on to evaluate and the other I bought new for a too good to pass up proce. They pretty much sit on the shelf, but I figure they will be sort of rare like the Pilot in 20 years as, like the Pilot, they only stayed in production a couple years.

My main irritation in the water is that the X650 has really poor case geometry fault issues. The top of the exhaust valve is well above the center of the diaphragm in a normal swimming position - a really bad idea, as it means in between breaths, air will leak out the exhaust valve allowing the diaphragm to rise and put pressure on the lever. If the reg is adjusted to breathe too light, the lever will be moved enouigh to allow a slight freeflow betwene breaths.

So in effect, if the reg does not freeflow above water and only freeflows in the water, the odds are that it is just adjusted too lightly to be fully stable in the water.

In playing around with mine, I found that you had to adjust the orifice to produce an inhalation effort of about 1.2 to 1.4" of water to prevent a slight freeflow between breaths. Adjusting the adjustment knob does not really resolve the problem as it still allows the full range of lever movement and you never really get ahead of that issue. In contrast, adjusting the orifice lowers the lever slighty and minimizes the CGF issues.

This is kinda sad as the poppet assembly itself is superb and would allow an inhalation effort as low as .6" and it would be useable if the X650 had the same coaxial exhaust valve and dipahragm as the D400.

 

[merxlin]

Thanks DA. Turns out my usual LDS is closed for a week, so I took it to another shop that I trust. The IP's are all right where they should be, but we detuned the second stage a bit anyway to get rid of the slight freeflow. I'll see how it does at 100ft+ Saturday. Think I'll put the good octo on and bring the pony..........(would have anyway).