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What exactly would happen if you went Nitrox diving with incompatible regulators?
I did a Nitrox course recently but none of us checked that our regulators were Nitrox compatible. At 15m my second stages (both) just stopped working. I took them to be serviced and the technician said that the low pressure seat in both of them had failed simultaneously. Is that something that nitrox would cause?
My second stages are Italian made Performance brand (nothing fancy), my first stage is Scuba Pro MK18 - I'm not sure whether they are nitrox compatible and I don't know if the technician guy looked at the first stage as well. This happened abroad - he didn't service them there as he didn't have the parts, I will have them serviced before I dive again anyway.
You're second stages are low/no quality. They would have failed no matter what you were breathing would be my guess.
Using "nitrox" in regulators without "nitrox compatible" parts can result in the need for more frequent servicing, viton o-rings last longer in O2 rich environments. Spontaneous failure is unlikely in my opinion.
I strongly recommend against using low end equipment, particularly when it comes to regulators.
Truth be told. The ind. standard is "All regs should be Nitrox compliant up to 40% O2". REgs "Shouldn't" need to be O2 cleaned unless you are going higher than 40%.
Agreeing with the other 3 folks below, and: 1.Any standard nitrox mix should not hurt your reg. 2.It is highly unlikely that both second stage seats would fail simultaneously. (It is likely that a seat failure would cause freeflow) 3.I would bet that your first stage is to blame and stopped delivering gas to either second.
JMO
Norm
Yes I was at 15m, my air supply suddenly stopped, I tried my alternative which also wasn't working so I had to swim for my buddy's alternative which worked out ok. I think I was about 20 mins into the dive. During the safety stop my regulator seemed to be supplying air again. At the time I thought it was too much of a coincidence that it happened during my Nitrox course. But maybe it was just pressure related and needs a servicing. Scubapro's website doesn't give any information about it. Does anyone know if there's some sort of problem with MK 18 first stages? Scubapro doesn't make them anymore but I never heard of a recall.
then 1st stage lock up (very rare), out of air OR a tank valve being turned off would be the most likely culprit. What was your SPG reading when this happened??? Did you try your reg on another tank? Most all regs (except Posiedon) use down stream secondaries. They should fail in free flow mode.
Usually when a seat (or spring) fail, the first stage goes into free flow mode... causing either or both of the secondaries to go into free flow. Trash (from a non-O2 cleaned tank) can clog some of the balancing mechanisms to the point of restricting air flow or a corroded piston bind can do the same thing. Both of these are quite rare.
It is rare that an equipment failure would cause air to stop flowing. Since you stated that air flow resumed later in the dive, I wonder if your tank valve was not fully open.
If a tank valve is opened only slightly, the air pressure in the lines drops with each breath. Between breaths the line pressure builds again. As you go deeper and as tank pressure drops you may experience an out of air sensation when line pressure drops to nil.
If that's not it, then I'd next suspect a physical obstruction in the tank valve from debris and crud in the tank.
Regardless, I doubt that nitrox played any role in this situation.
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Was your tank valve fully open?
