It finally happened - my CCR tried to kill me

[stuartv]

4) You have your own SOP to build the unit. Paul Raymaeker wrote a build list for a reason. I have packaged it in X's rEvo checklist (Google app). There is a reason for each step and their order. Now you have just demonstrated why installing tanks come after closing the lid.

5) You figured out that your breathing was abnormal and you did not abort. I'll guess you will reconsider next time .

6) You realized that some cells were reading crazy, but you decided that a few of them were nevertheless worth trusting. I don't recall reading that you did a loop flush to check them out. Granted, if they were all connected to a single computer, the computer could be suspected, but yours is probably hard wired, so connections are not very sensitive, unless you snagged the cable (has happened to me, with predictable consequences - which I discovered post dive, but still worked fine).

7) I can't resist to express my surprise that the incomparable rMS did not pick up the flood...Shocking.

Dive safe (or don't dive... it amazing how easy it is to do, in retrospect).

My Build checklist occurs after the tanks and scrubber cover are on. I have not seen an actual build list of how to put it together. Regardless, if you think that this demonstrates why installing tanks comes after closing the lid, I think you have misread my report in the same way that several other people did.

I didn't call out the various loop flushes I did as details. They are implied in "knowing" what cells are reading correctly.

I'm not sure how "if they were all connected to a single computer" is meant to be taken. I thought it was clear in my report than they were not. As well, I indicated that I have rMS. If you know rEvos, then you would know that that implies that the controller is connected via a 5-pin wet-mateable connection. My NERD2 is connected to its sensors via a 4-pin wet-mateable connector as well.

I'm not sure why you would expect the rMS to pick up the flood? My CO2 reaction front was still in the top basket. Only the bottom basket area of the unit was flooded. That kind of sounds more like a backhanded dig at the rMS system than a sincere comment?

 

[Snoweman]

i find that hard to believe i lubricate all o rings on every piece of equipment (except my shearwater battery cap ) and never had a leak on anything - rEvo manual tells you to lubricate the lid o rings

Are you not supposed to grease the O rings on a shearwater?

 

[lermontov]

Are you not supposed to grease the O rings on a shearwater?

im not aware you shouldn't - just haven't

 

[Snoweman]

im not aware you shouldn't - just haven't

I checked with shearwater. They recommend lubricating the rings with every battery change. As a vacation diver, I take out the battery between trips. I wasn't lubricating until a DM in Coz told me to do so. Now, I do it when I put the battery back in.

 

[Heat Miser]

Now you have just demonstrated why installing tanks come after closing the lid.

I don't get this installing the tanks is one of the first things you do an comes before checking o-rings and screwing on lid?

http://www.revo-rebreathers.com/wp-content/uploads/2016/02/rEvo_checklist_v04_031013.pdf

Are you Irvining* us up?

 

[davehicks]

Here is the simple rule for lubing O-Rings

• If it slides in or rotates then lightly lube it.
• If it simply compresses in a grove don't lube it.

So lube the Shearwater cap, don't lube the battery box or camera back.

 

[Wibble]

I re-formatted the Revo checklist for the specific case of a R19 Revo - Petrel controller, Nerd backup, no RevoDreams.

I added space to be able to record various settings -- mV, pressures, etc. -- and turned it into a checklist. It's formatted such that if you print it as double-sided A5 (that's roughly half a letter page), it is clear enough to read and small enough to keep.

I've a version that has two copies on each side, so you can print of a few dozen and guillotine it in half.

(Should I create a new thread with this checklist?)

 

[Compressor]

I've been feeling pretty lucky to never have felt like I'd had an "oh, ****" moment while diving my rEvo. That is now behind me.

Short version: I was diving the Lady Luck in south FL on Sat. My unit passed a negative test before I got in. Then it proceeded to very slowly start flooding once I was in the water. At about 45 minutes in, I felt like it wasn't breathing right, but I wasn't sure if that was just in my head or not. I switched to BO and obviously that felt much better. I went back on the loop and it was the same, but I stayed on it. Partway up in my ascent, 3 of my 5 O2 sensors started giving me completely whacked out readings. All 3 were ones connected to my Predator controller. The 2 that are completely independent and connected to my NERD2 continued to read correctly and I completed my dive following my NERD2. My post-dive inspection found both scrubber baskets totally soaked. The exhale (top) counterlung had a normal amount (for a 90 minute dive) of moisture in it. The inhale counterlung has a LOT of caustic water in it.

"But did you die?" No. But, I think I felt the puff of air as the bullet went past my head.

Long version:

I got to Pompano Beach last Wed afternoon. I started to prep my rEvo for a blackwater night dive and immediately figured out that on my last dive before this trip my battery box had flooded. The circuit board inside it was toast. I scrambled around and was able to score a brand new replacement first thing the next (Thu) morning. I installed it and just barely was ready to dive in time for my boat that day (which was very fortuitously not scheduled until 1pm). My rEvo worked just fine for that dive. Post-dive cleanup, it looked totally fine on the inside. No unusual anything.

Fri morning, I dived again. My rEvo worked just fine again. Again, post-dive maintenance was totally normally. I opened it up, cleaned it up inside. There was normal moisture. It stayed open to dry out overnight.

Sat, we were back to diving in the afternoon. So, I prepped my unit at a leisurely pace that morning. The only unusual thing that I remember is that I had some trouble getting the scrubber cover to fully seat properly. I realized it was hitting on the O2 cylinder just a little bit, so I pushed the O2 cylinder to the side and the cover dropped into place. I put on new cylinders every day, so the ones for Sat were not the same ones I had used on any prior day.

I didn't think any more about that (my mistake!) and went through my Closed check list, which it passed (including a Negative test).

We splashed on the Lady Luck. It offers more depth, but I stayed on the main deck the whole time, so never went deeper than 125 feet. It was my first dive of the trip where I took my camera in the water. I was diving with 3 other guys who were all on OC (doubles, with deco cylinders). When we got down to the main deck, I started setting up my camera and dialing in settings. They took off and left me. Not unexpected. I swam around the main deck and ran into them once or twice. I noticed a couple of times as I swam around that it felt like it was just a tiny bit harder to inhale than normal. But, I was swimming slowly, not exerting myself, and it only caught my attention a couple of times, so I thought it was probably just in my head.

About 30-ish minutes in, I met the other guys back on the stern, where our boat was tied in. They signaled that they were going up ('cause OC sucks! LOL) and waved goodbye. I signaled that I would go up with them, but they gave me a questioning look and I thought "yeah, why go up now? I can stay down a lot longer than this." So, I stayed.

I made another lap of the main deck. Took some pictures. Dropped down into an open hold and came out. I started making my way back to the stern.

I should also note that on this day, my mask decided it was going to leak constantly. Most days, it only leaks a little. And usually not much at all until I start my ascent for some reason. But on this day, I was having to clear it constantly. So much that when I tried to take a picture of something on the floor, I really couldn't. I would clear my mask then try to look down through my camera's viewfinder and I would already have enough water in my mask that it would obscure my vision when I tried to look straight down.

So, now I'm 45 minutes in and almost all the way back to the stern to start my ascent. At this point, the work of breathing definitely seems a bit harder than normal. I decided to switch to bailout to see how that made me feel. I flipped my BOV to BO and breathed from that for the few seconds it took to pull out my OC BO reg and switch over to that. I mention that because that proves to me that I did in fact close the loop before I took it out of my mouth. Switching the BOV to BO IS how you close the loop.

Anyway, that dive being relatively shallow and knowing the other guys were not going to be doing a long dive, I only took one BO gas with me. An AL80 of TX18/45. It was plenty to get me out. But, I also knew that if I did my deco on that it would take a lot longer than if I stayed on the loop. So, I decided to switch back to the loop for my ascent if it seemed okay. I switched back and it was the same as before. Okay, but not "normal". But, my ppO2 was good and my rMS showed that my scrubber was still working off the top basket - not even into the bottom basket yet. I made the decision to continue my dive on the loop.

I started up the anchor line. Partway up, all my O2 sensor readings on my controller, and the first sensor shown on my NERD just went haywire. 2 of the ones on my controller were showing 0.5 - 0.6, but #3 was showing 2.50 or something like that. #3 is shared via a splitter with my NERD. It is in position #1 on my NERD. #1 on the NERD was also showing the same effed up reading.

By this time, I was shallow enough that I knew I couldn't really have a ppO2 that high. And #s 2 and 3 on my NERD were still showing the expected values. So, I spent all my deco time at 20' and up just tracking #s 2 and 3 on my NERD and following the ascent it gave me. My controller had 2 sensors that were reading way low and one that was way high. The two low ones were pretty close, so the controller voted out the 3rd and it thought I got out with about 5 minutes of omitted deco. But, I knew from my depth and doing O2 flushes that the 2 sensors on my NERD were correct and I followed its ascent plan.

After I got out and got back to my hotel I opened up the unit. Both scrubber baskets were totally soaked. I presume that is what made it feel a bit hard to breathe. The top CL had a normal amount of lung butter in it, but no more. But, the lower CL had a ****-ton of water in it. I put my fingers in that water and a small nick on one finger instantly started to sting.

During my ascent, I rolled onto my side a few times to look up, to make sure I didn't ascend into a diver above me. I am thinking that one of those times rolling on my side resulted in that caustic water to getting on 3 of the sensors. I reckon that is when my readings all went haywire.

When I saw what was up inside my unit, I realized that if I had just happened to go into a head down orientation, that caustic water would probably have run right down through my inhale loop hose and I would have inhaled a big mouthful of it. I'm thinking that would probably have been really bad news for me...

I cleaned it all up that night and left everything open to dry. The next morning, I packed new sorb in both scrubber baskets. I checked the O2 sensors and 2 of them were still giving squirrely readings in air, so replaced them. I put on new cylinders and went diving at the Blue Heron Bridge. Max, 20 feet of depth. That seemed like a reasonable option for testing it out to see if it was back to working okay.

Sure enough, it worked fine. We did 100 minutes in the water and when I opened it up afterwards, it did not have any excess water inside.

I have been replaying the whole weekend in my mind over and over. Another small point clicked. When I was removing one of the cylinders from the rEvo at some point, I noticed that I had done a whole dive with it on my unit and one of the little "feet" of the mounting bracket was not actually down in the slot it was supposed to be in. At this point, I'm about 90% certain (only 90% because my memory seems **** these days..) that it was the O2 cylinder that I had on during the dive where it flooded. Meaning, when I assembled the unit in the parking lot of the BHB, I removed the cylinder I used the day before (during the Lady Luck dive) and that was when I noticed the tank fixation wasn't fully seated.

So, I am about 80% confident (because I like to arbitrarily quantify stuff) that what happened was that I didn't get the O2 cylinder's mounting bracket seated properly when I installed that cylinder on my rEvo on Sat morning. That resulted in the cylinder being twisted out of its correct position just enough to interfere with the scrubber cover. I was pushed it to the side and got the scrubber cover to seat. But, my theory is that it was still pushing against the side of the scrubber cover after everything was fully assembled.

And that resulted in just enough of a leak that it passed a somewhat cursory negative test, but still allowed a slow leak in the water.

Epilogue: I learned several things through all this. Quite a few, really. And I have some testing to do. Meanwhile, I'm sure a number of you (if you actually read this far) will have some good opinions on various mistakes that I made. I welcome hearing them. I wouldn't be sharing this story if I didn't hope to learn more from some of you. I'm just glad to still be hear to take the criticism!

Glad you are ok. Thanks for sharing with us.

 

[uwxplorer]

My Build checklist occurs after the tanks and scrubber cover are on. I have not seen an actual build list of how to put it together. Regardless, if you think that this demonstrates why installing tanks comes after closing the lid, I think you have misread my report in the same way that several other people did.

I don't understand the first sentence.
I did not point out the defective tank bracket as another complacency point, but my point was that once the cover is installed, comes the tanks. Obviously, if anything is wrong with this later stage, you (I) have to ask yourself (myself): how far away from the safety envelope am I?

I didn't call out the various loop flushes I did as details. They are implied in "knowing" what cells are reading correctly.

Well, there are so many "implied" steps that you skipped, that I had to ask...

I'm not sure how "if they were all connected to a single computer" is meant to be taken. I thought it was clear in my report than they were not. As well, I indicated that I have rMS. If you know rEvos, then you would know that that implies that the controller is connected via a 5-pin wet-mateable connection. My NERD2 is connected to its sensors via a 4-pin wet-mateable connector as well.

I meant that the wet matable cable is much more reliable than a Fisher connection, and that the on chip digitization of the signal would exclude that the cable was responsible, so a priori you should have concluded that something inside the canister (chip, or most likely cells) was acting up. What I don't understand then, is how you could hope that some would reliably and durably provide trustworthy information. But in the heat of action, I get that we all have judgment lapses.

I'm not sure why you would expect the rMS to pick up the flood? My CO2 reaction front was still in the top basket. Only the bottom basket area of the unit was flooded. That kind of sounds more like a backhanded dig at the rMS system than a sincere comment?

Jab at the rMS... There were reports by fanboys in the early days, that not only did it keep them from peeing in their wetsuit and helping with their trim, but it had even started to act up when a partial flood had developed in their unit, unbeknownst to them...
In retrospect, it was probably starting to fail, like yours will (again) eventually.
I will never warn people enough to NOT trust the rMS especially in dire situations.

 

[Tassi Devil Diver]

I will never warn people enough to NOT trust the rMS especially in dire situations.

Not sure what sort of possible dire situations you may be referring to, after nearly 500 hrs on the rEvo I have found the rMS predictions of scrubber time to be very robust, I am satisfied there is more than adequate conservatism built into the scrubber time prediction algorithm to be able to trust the rMS in a "dire situation" (I have run my rEvo scrubber 30 minutes beyond 0:00 RST under instructor supervision with no ill effect, ).

Whilst I have had more than my fair share hardware failures with 13 probes replaced under warranty in the first three years, I have found the rMS hardware over the past three years to be solid.