Question CCR for recreational depths

[rjack321]

Except that a blocked orifice is very unlikely. On an eCCR with electronics, wiring, batteries, etc there are far more likely failure points.

Very unlikely? Au contraire, in only the last 2 years I have 2 buddies with blocked orifices. Both were 0.035" size and not even the tiny tiny ones. They happen more often than you'd think.

@nadwidny had a partially blocked orifice on an actual dive which he's written about elsewhere on SB.
@girlwithbigtanks had a fully blocked orifice on a used unit she bought, we discovered it on the surface. Unit only had 50 hrs on it.

There's a valid reason for the relative popularity of blocked 1st stages with needle valves.

 

[Wibble]

Ehhhhhh. More like take appropriate low PPO2 breaks.

But... that means switching to OC bailout every ~30 mins. O2 rebreather doesn't have diluent. Suppose a lungful of air from the bailout puffed into the loop might help. Do O2 CCRs have oxygen sensors?

 

[davehicks]

Very unlikely? Au contraire, in only the last 2 years I have 2 buddies with blocked orifices. Both were 0.035" size and not even the tiny tiny ones. They happen more often than you'd think.

@nadwidny had a partially blocked orifice on an actual dive which he's written about elsewhere on SB.
@girlwithbigtanks had a fully blocked orifice on a used unit she bought, we discovered it on the surface. Unit only had 50 hrs on it.

There's a valid reason for the relative popularity of blocked 1st stages with needle valves.

Had they ever serviced their MAV to clean the orifice? Did their MAV have a pre-filter?

I now typically do this every January and put the thing in my ultrasonic. Sort of like replacing smoke alarm batteries annually. But for a long time, I didn't and never had issues. I did once have a problem where the MAV was leaking in TOO MUCH O2. A simple rebuild and cleaning fixed that.

Regardless, it's uncommon. Even if clogged, pressing the MAV will still inject O2 on most systems.

 

[grantctobin]

Regardless, it's uncommon. Even if clogged, pressing the MAV will still inject O2 on most systems.

Still happens more than you’d think and probably more often than a solenoid fails. Doubly true on the ****** Revo pressed in orfice that can’t be serviced.

Signed, uses a needle valve now

 

[sprockjohnson]

Doubly true on the ****** Revo pressed in orfice that can’t be serviced.

Yep. Had that happen to me last year. Cut the shrink tubing on the orifice assembly, disassembled as much as possible, and soaked in a water/ vinegar mix for a bit and luckily it unclogged. I'm looking at going the needle valve route sometime in the future.

 

[grantctobin]

Yep. Had that happen to me last year. Cut the shrink tubing on the orifice assembly, disassembled as much as possible, and soaked in a water/ vinegar mix for a bit and luckily it unclogged. I'm looking at going the needle valve route sometime in the future.

If you’re really in a pinch, you can leave it in an ultrasonic for a (very very) long time. That said, they’re better used as a seal clubbing tool and then thrown out.

 

[The Chairman]

The wing will be functional.

The wing is always functional. The ADV has no effect on that.

 

[broncobowsher]

The wing is always functional. The ADV has no effect on that.

Are you talking ADV shut off, or DIL shut off? I was not counting on just an ADV shut off. I was thinking complete DIL shut down.

 

[girlwithbigtanks]

Had they ever serviced their MAV to clean the orifice? Did their MAV have a pre-filter?

I now typically do this every January and put the thing in my ultrasonic. Sort of like replacing smoke alarm batteries annually. But for a long time, I didn't and never had issues. I did once have a problem where the MAV was leaking in TOO MUCH O2. A simple rebuild and cleaning fixed that.

Regardless, it's uncommon. Even if clogged, pressing the MAV will still inject O2 on most systems.

In my case i knew the 02 wasn’t flowing when i built at home. I had ordered spares but thought i forgot to order orfice tool. @rjack321 had the tool & flow meter. I had a brand new spare orfice. I am not convinced I’m going to use the stock dual mav so was just a test splash. Everything i can take apart has now had a nice ultrasonic bath. The guy using it before me would have had no flow.

 

[The Chairman]

I was thinking complete DIL shut down.

Again, why? My o₂ bottle will outlast my scrubber. Why limit your options? I thought that 20FSW was the deepest, but now I'm at 25 FSW. I don't know about you, but I hate alarms, so add a little dil and keep diving.