Reg lockup

[SteveAD]

Did you have some particular damage in mind that might have caused this intermittent failure?

Dave C

The symptoms have me completely baffled. The quirky nature of the original mk16 design is that it had a plastic Hp seat and a round metal poppet. If the plastic seat was installed without the mk16 seat tool it was almost guarunteed to get dinged in some way that would cause the IP to creep up to the point of a freeflow. On several occasions even using the tool I had them get dinged and had to replace the new seat with a new new one. It is absolutely not something that can be disassembled and reassembled without using new parts. The mk17 style upgrade makes the HP seat much less damageable but still a PITA to install without the right tools.

 

[dave4868]

I have a "new to me" set and just had this problem happen with my ScubaPro R190 (I think that's the model). It's gotten me through a dozen dives but as I was getting in the water last time, I took a breath to test the octo and it just locked up. My IP was good and a trusty old Sherwood replacement got me through the dives.

It's been a few months since I've done it so forgive my lack of detail (or accuracy)...

Since I know the people in my LDS that would soon be doing the service I opened it up to see what the issue was. I figured worst case I take it back to them in pieces and they make fun of me. Best case I fix it then take it in and say "I fixed it, now fix it right". I had good guidance from Vance Harlow's "Scuba Regulator Maintenance and Repair" book in the meantime.

My problem seemed to be in the lever that works the poppet. I opened the front cover and the lever was laying flat against the poppet housing. I lifted it back up to a "rest position" and gave it air, pressed the lever and it worked fine. Every couple of tries though, instead of folding down and opening the poppet, it folded down then seemed to lose it's grip on the poppet and lay flat against the poppet housing. I pulled the poppet out and removed the lever. An experienced person may have noticed something installed backwards or bent but it looked OK to me. I don't recall if I tweaked the legs of the lever as it hit the poppet but I reassembled it the way it seemed to want to go (and per the book), gave it air, and it worked flawlessly.

My best guess is either the poppet was in backwards or the lever needed a slight tweak. No debris, no rotting nor any other causes typical of complaints in other online posts. I'm taking it to the shop next week so I'll find out what I can from someone with experience. Best of luck with yours!

Very interesting.

If you take a look at Frogkick's Scubapro manuals in the following link and open "11-3xx-000 R190 Rev U.pdf" "283 KBytes" maybe you can determine from the schematic if your poppet lever/assembly was correctly installed:

http://www.frogkick.dk/manuals/scubapro/Schematics/2. Stage/

Please post what you think.

Dave C

 

[redacted]

Very interesting.

If you take a look at Frogkick's Scubapro manuals in the following link and open "11-3xx-000 R190 Rev U.pdf" "283 KBytes" maybe you can determine from the schematic if your poppet lever/assembly was correctly installed:

http://www.frogkick.dk/manuals/scubapro/Schematics/2. Stage/

Please post what you think.

Dave C

OK, I had to go find an old R190 and look. With lots of crap in the case you could get something big stuck between the lever and the case (were you missing a pet mouse?) and keep the lever from depressing freely. Or something smaller (I did it with a piece of toothpick) could get stuck between the legs of the lever and the case or the housing and interfere with lever operation. Beyond that and to address AngryJonE5's experience, You might get enough wear or damage on the feet of the lever that a foot does not engage the washer and lift the poppet. Properly adjusted, the lever is loose and will slide side to side 1mm at most when the valve is closed. That could explain the erratic performance. But such damage/defect on the lever should be quite obvious on disassembly. Short of that, when the lever is pressed, the poppet lifts and the valve opens.

 

[NancyLynn]

Very interesting.

If you take a look at Frogkick's Scubapro manuals in the following link and open "11-3xx-000 R190 Rev U.pdf" "283 KBytes" maybe you can determine from the schematic if your poppet lever/assembly was correctly installed:

http://www.frogkick.dk/manuals/scubapro/Schematics/2. Stage/

Please post what you think.

Dave C

Cool! Now when I get a spare to play with I'll be able to tell what I'm playing with!:book2:

Short of installing the diaphragm on the wrong side of the lever, I'm still not seeing what could have sounded/felt like the failure. Hmm. I'll have to keep thinking.

 

[Celt5494]

Did you pre-breathe your regs before you got into the water? I will normally give them a few seconds of stress breathing to ensure all are functioning correctly. What regs/1st stages were you using? In the long run ****e does happen and it's imparative to prepare for it to happen at the worst possible time. Glad you experienced this above the waterline rather that @ 120 FSW and have such a malfunction during an otherwise fun dive.

 

[NancyLynn]

Did you pre-breathe your regs before you got into the water? I will normally give them a few seconds of stress breathing to ensure all are functioning correctly. What regs/1st stages were you using? In the long run ****e does happen and it's imparative to prepare for it to happen at the worst possible time. Glad you experienced this above the waterline rather that @ 120 FSW and have such a malfunction during an otherwise fun dive.

Yes - did breathing from both reg and octo before entering the water. And as I did my giant stride off the boat. And on the surface while waiting for everyone to get in the water. And it breathed just fine the next morning for a while, then locked up again. (And I understand it was still breathing just fine hanging out in the shop while they tried to figure out what was wrong.)

You're right - I need to be prepared for it to happen at the worst possible time. Part of that preparation for me is to pick apart this incident to try to figure out what to do when I learn I have a breathing system symptom in a safe location. How do I reliably figure out the source of the problem so so I know how much to swap out so that I can continue to dive safely until I can get the problem part/parts back to the shop. It would be no fun to successfully avoid diving with a problem second stage only to discover at 120 feet that the problem wasn't really the second stage and neither the replacement second stage nor the octo works.

That's where you all come in - thanks for all the good suggestions for troubleshooting/field tests so far.

 

[redacted]

I tried to take a breath, it sounded and felt like trying to breath through a tube which had a piece of rubber sucked against it and got no air. My octo worked fine.

One other thought and I'm really stretching here. It is not a problem I have encountered but it may explain your symptoms. New R-series regs have the seat glued into the poppet with a little rubber cement. It is not very strong but holds the seat in place. When I rebuild my regs I never use any glue and I suspect most techs don't also. The tight fit and downstream & spring pressures seem to hold the seat in place. But total poppet movement is about the thickness of the (rubber) seat and should the seat somehow slip out of its pocket it could wedge between the edge of the poppet and the orifice knife edge and severely limit gas delivery. And pushing the purge button hard enough might also pop it back in place, easily if the gas is off producing the variable symptoms. If you can't find any other explanation, it may be worth a check. If the shop can reproduce the failure, they could leave the reg assembled and remove just the orifice and see if the seat falls out behind it.

I was initially thinking a hose defect and, although the hose seemed to work OK on the rental 2nd, I don't think that possibility has been totally eliminated.

 

[tfsails]

awap (and NancyLynn)--If the poppet seat is loose in the poppet and the demand lever is actuated (either by breathing or purging), air pressure upstream of the poppet will force the seat away from the orifice and air will flow.

I've read every reply in this thread and I think you had two problems: a blockage of some sort restricting air flow to your primary reg, and the creeping IP in your first stage causing free flowing of your octo, which is working as advertised when it freeflows.

Let's take these problems in order. First, a Scubapro R190/R380 is so dirt simple it is virtually impossible to screw it up when you put it together. The Nyloc nut (a/k/a self-locking nut) has a nylon ring that grips the threads of the poppet and prevents it from unscrewing itself as the reg is used. That nut is replaced during every service. It should NEVER be re-used because it loses its self-locking properties once it comes off the male threads of the poppet. If that nut were installed too loosely, it is conceivable that it would be so loose that the demand lever would not move the poppet when pushed. Basically, it would just be rattling around moving nothing. If this were the case I'd suspect that it would show up immediately when you turn air on.
Also, if the demand lever were installed above the washer instead of below it, its tangs may not move the poppet. The washer must be between the demand lever and the nut.
Third, the p/n 21080121 housing insert (item #30 on the R-190 schematic) may be broken. I've had this happen to me on an Air 2 that I rebuilt. The protrusions on it can break and fall away, and the demand lever will not have a surface to push against as it tries to open the poppet. This, too, once it happens, should not "fix itself" at any time. Key word here is "should not..."; anything can happen. These protrusions would fall away from the demand lever and probably be blown out into the water during exhalation. I wouldn't think they would get inside the pressurized part of the reg.
It is impossible to mount the diaphragm on the wrong side of the demand lever, so you can forget that idea.


Second--the creeping IP is a first-stage problem and rebuilding the first stage should fix it. Be sure to tell your technician to look for FOD (foreign object debris--a military term) inside the low-pressure side of the first stage that could block a hose port and cause your primary second to lose air flow. I've never seen a first-stage creep that couldn't be fixed by rebuilding the stage. This shoud be done every time the stage is serviced. If it's not done, your LDS is shortchanging you and you need another LDS.

I'd love to see your reg and see if I could duplicate the malfunction and see what fixes it. If you REALLY want to get to know regulators, you should read the book "Regulator Savvy" which is available at Peter Built tools Peter Built Co. . It's well worth the price and it taught me more about regulators than any factory service manual I've ever read.

 

[NancyLynn]

I think you had two problems: a blockage of some sort restricting air flow to your primary reg, and the creeping IP in your first stage causing free flowing of your octo, which is working as advertised when it freeflows.

I didn't have octo free-flow - although, now that I think back the replacement reg was leaking air part of the time when I was not actively using it. Makes sense.

It is impossible to mount the diaphragm on the wrong side of the demand lever, so you can forget that idea.

Yeah, I know - I wasn't seriously suggesting that was the problem. It's just that my immediate reaction (before I looked at diagrams of the innards) was that that it sounded and felt like trying to breathe through a piece of rubber across my breathing tube. The only piece that fits that description of the blocking item and the only orifice that it could block that would cut off air as I inhale would be the diaphragm on the wrong side of the demand lever.

Second--the creeping IP is a first-stage problem and rebuilding the first stage should fix it. Be sure to tell your technician to look for FOD (foreign object debris--a military term) inside the low-pressure side of the first stage that could block a hose port and cause your primary second to lose air flow. I've never seen a first-stage creep that couldn't be fixed by rebuilding the stage. This shoud be done every time the stage is serviced. If it's not done, your LDS is shortchanging you and you need another LDS.

They're rebuilding it, and upgrading to the equivalent of the MK17 (which, as I understand it, replaces a plastic part with a metal one). I'm confident the tech working on it will thoroughly check everything out - and yes (to the extent I can tell without tearing the reg apart) - they rebuild the stage every time they service it.

If you REALLY want to get to know regulators, you should read the book "Regulator Savvy" which is available at Peter Built tools Peter Built Co. . It's well worth the price and it taught me more about regulators than any factory service manual I've ever read.

Thanks! I've bookmarked the order page for future reference.

 

[EricQ]

awap, you could be onto the problem with the seat movement. I don't recall from memory if the R190 poppet has a relief hole; but if it does not, then a pinhole in the seat could produce this symptom, and may not produce it all the time.