Should a regulator "cut off" when you are upside down?

[kidspot]

Just a question of how common and important this is. I'm in the middle of my BOW cert and the first dives we did I was borrowing one of the instructors regs, which stopped delivering air when I would look up or roll over. Looking down you could feel the resistance get a lot less. He said it wasn't suppossed to do this, and the next class brought another one for me to use (btw - both were Scubapro regs - I think an RB380 2n'd stage & MK25 first) The reason I ask is because 2 of the other students have said the same thing about their regs (all ScubaPros - 4 students total, 3 with this problem) The replacement reg was fine - what would cause a reg to do this and how common is it?

Tim

 

[Don Burke]

Just a question of how common and important this is. I'm in the middle of my BOW cert and the first dives we did I was borrowing one of the instructors regs, which stopped delivering air when I would look up or roll over. Looking down you could feel the resistance get a lot less. He said it wasn't suppossed to do this, and the next class brought another one for me to use (btw - both were Scubapro regs - I think an RB380 2n'd stage & MK25 first) The reason I ask is because 2 of the other students have said the same thing about their regs (all ScubaPros - 4 students total, 3 with this problem) The replacement reg was fine - what would cause a reg to do this and how common is it?

Tim

Every reg I can think of will do this if the second stage cracking pressure is set a little high.

It is common.

It is not right.

 

[kidspot]

so it's a simple solution - though I thought I had the adjustment knob turned to the most sensetive position - I must have done the opposite - all the "little" things to learn!

Thanks,
Tim

P.S. Is there a standard ie clockwise for easier breathing, counter clockwise for pre-dive?

 

[rescuediver009]

Counterclockwise to loosen the resistance. Or you should notice that the screw will come out a bit. Sometimes it is not necessarily cut off but the geotmetry of the regulator and the relationship of the position of the diaphragm to the regulator body could cause the water sitting on the top of the diaphragm to weigh down on the air inside. (if this makes sense) And you have to draw down on the air that wants to go up as always in water. This creates more resistance. Sometimes so much that it feels like it is cut off.

simply put regulators are dseigned to be breathed straight up and down or horizontally as in when swimming forwards.

 

[kidspot]

yup - makes sense - There is only about 1/4 - 1/2 inch of "turnability" so i assume it's a dive/predive switch, but not labeled which direction was which and I had trouble determining which was easier to breathe from. Either way I felt like I had to inhale quite hard to get the air flowing - the "cracking pressure" was similar to what it takes for me to blow up a balloon initially (I used to be a clown - so lot's of "hot air" to work with - lol) I have my own reg, which I got to breathe off of during an air share drill (Kirby Morgan Superflow) sooo much easier to breath off of. But I'm loaning it to my future Dive buddy since we only had 1 rig between us and the instructor's BC's all used a proprietary Air2 hose on them . . . Bummer.

Thanks for the info though - I'm hoping the second set of gear arrives this week so I can continue learning in my own rig (currently held up by the USPS for several weeks . . . somewhere between New Jersey and Hawaii - the joys of priority mail, but that's for the "whine and cheese" section)

Tim