press purge button when opening tank valve?

[TCDiver1]

I haven't sliced a low pressure hose either, but it couldn't possibly empty a tank faster than just cranking the valve open. All a regulator is is a passive series of restrictions to gas flow, it doesn't somehow amplify the gas delivery capability.

Lol, i never said it would amplify the gas delivery. Just that i doubt most would open a tank valve enough to match the fix pressure flowrate that could be put out by a regulator 1st stage with a cut hose.

It would be really loud for one thing and as Mark alluded to, might scoot around the room if not bungied down real well. 3000 little psi's, trying to squish through that small valve hole at the same time could be loosely called "jet propulsion".

 

[jonnythan]

Lol, i never said it would amplify the gas delivery. Just that i doubt most would open a tank valve enough to match the fix pressure flowrate that could be put out by a regulator 1st stage with a cut hose.

It would be really loud for one thing and as Mark alluded to, might scoot around the room if not bungied down real well. 3000 little psi's, trying to squish through that small valve hole at the same time could be loosely called "jet propulsion".

I dunno. The air coming out is very non-directional, though the net force will of course be backward. I've opened mine pretty far and not noticed any really significant force.

If you plugged all the holes in a first stage, then drilled a 1/2" hole through the bottom to direct the airflow, then I'm sure you'd get a very nice amount of propulsion

 

[tinman]

I do it with my Mares Abyss. They have a somewhat sensitive HP seat.
It was recommended to me by the LDS where I bought it.

Ditto, but not when diving this time of year. It would be nice to get a definitive answer on this one...is this an old diver's tale or not?

 

[simbrooks]

How bad is the reduction in life of purging whilst opening slowly compared to just opening slowly? Then compare opening quickly to opening slowly. It does sound like an old divers tale, it sounds plausible, but i certainly wouldnt know one way or the other - as stated above, assuming you get your regs serviced once a year/100-150 dives are you really going to notice this difference?

 

[TCDiver1]

I dunno. The air coming out is very non-directional, though the net force will of course be backward. I've opened mine pretty far and not noticed any really significant force.

If you plugged all the holes in a first stage, then drilled a 1/2" hole through the bottom to direct the airflow, then I'm sure you'd get a very nice amount of propulsion

Okay, i'm done. Yet again, i wonder why i ever get into these things? :06:

simbrooks,
in my experience, it makes little difference.

 

[Hank49]

How bad is the reduction in life of purging whilst opening slowly compared to just opening slowly? Then compare opening quickly to opening slowly. It does sound like an old divers tale, it sounds plausible, but i certainly wouldnt know one way or the other - as stated above, assuming you get your regs serviced once a year/100-150 dives are you really going to notice this difference?

Here's why I asked the original question. And it may all come down to reg design. I worked in a shop that rented the Mares R2, unbalanced (i think that's the number) I replaced hp seats in those it seemed every 8 dives or so. After a while I just flipped them over. The difference between that reg and an SP MK2 or US divers unbalanced was that the HP seat just slightly stuck out past the piston sleeve, which would mushroom and leak very quickly. The hp seat on the SP and US DIvers were flush with the end of the piston sleeve and lasted for 100s of dives. I was going to try an experiment opening some with no purge and some by purging. But I had to get back to growing shrimp and never got around to it. Hank

 

[Greg Barlow]

Here's why I asked the original question. And it may all come down to reg design. I worked in a shop that rented the Mares R2, unbalanced (i think that's the number) I replaced hp seats in those it seemed every 8 dives or so. After a while I just flipped them over. The difference between that reg and an SP MK2 or US divers unbalanced was that the HP seat just slightly stuck out past the piston sleeve, which would mushroom and leak very quickly. The hp seat on the SP and US DIvers were flush with the end of the piston sleeve and lasted for 100s of dives. I was going to try an experiment opening some with no purge and some by purging. But I had to get back to growing shrimp and never got around to it. Hank

A number of dive buddies and I used Mares R2's for stage/deoc bottles for a number of years. I was the one rebuilding most of the regs, and I never have seen the nylon seats mushroom from usage. This reg is almost an exact copy of the MK2, and is basically about as robust as it gets. We switched to diaphragm regs due to diving in waters that get way below 50 degrees. Any unbalanced piston first stage can ice over in such conditions.

Greg

 

[simbrooks]

So would this be a problem only for piston 1st stages or do diaphragm 1st stages also get their HP their seat out of shape? I havent noticed my regs leaking after ~100 dives on them, nor in fact my last buddy's set (only 50 dives, but always jammed the valve open quickly) - of course i havent and dont intend to take them apart myself (at least not till i get some training in that kind of stuff ).

 

[Hank49]

A number of dive buddies and I used Mares R2's for stage/deoc bottles for a number of years. I was the one rebuilding most of the regs, and I never have seen the nylon seats mushroom from usage. This reg is almost an exact copy of the MK2, and is basically about as robust as it gets. We switched to diaphragm regs due to diving in waters that get way below 50 degrees. Any unbalanced piston first stage can ice over in such conditions.

Greg

Is there another model of Mares unbalanced piston made around 97-98? It was the same design as the mk2 and US Divers but the seat stuck out beyond the tip of the piston shaft by about 1 mm or less. Maybe the supplier in the Philippines was sending us the wrong seat too. ?? But they mushroomed. We had about 15 shop regs and I was fixing 3-4 a week.

 

[BlueDevil]

I started the practice of purging whilst opening the tank valve when i got my first Mares reg and noted in the instructions that this practice was recommended by the manufacturers. I figured that if the manufacturers recommended the practice thay must have a good reason for saying so. If this is a 'myth' then it is obviously one believed by a large and reputable company like Mares.