Stage Bottle - On or Off?

[DiveDocMD]

During my solo diver training I was instructed to pressurize the hose and second stage and then turn the valve off. Periodically during the dive, I would open and shut the tank valve to ensure that the hose remained pressurized. Obviously, if the pony were attached to the main tank you would have to leave its tank valve open.

 

[LiteHedded]

Pressurized and off. You do need to check the pressure frequently, because if it depressurizes, it is very possible to get water into the first stage, and it will ruin your pressure gauge.

very true

 

[SDAnderson]

Four divers in very cold water - near freezing. All have their stage bottles pressurized but turned off. Three suffer first stage freeze ups upon charging the bottles and have to feather them up to the next gas switch. All three were Apeks DS4s with Apeks 2nds. The belief (who knows for sure?) is that the 2nds purged and allowed water in the line, which (because the bottles/line are more or less horizontal) allowed water into the 1sts. Real world, cold water is a bitch.

Yep, should have paid more attention to the SPGs. Yep, should have probably stayed ashore rather than diving in 35F water on a -5F day. Now, if the water is really cold, I leave the valve open just a tick to make sure the system stays pressurized. I'll suffer a little bubbling in exchange for not having my tongue blasted with ice shards and having to add the task loading of working the valve all the way up.

 

[tflaris]

Off.

Pressurize it on the surface,check spg every so often. Repressurize if the second stage has been knocked and accidentally purged.

Ditto. In cave/tech diving the cylinder is pressurized only when breathing on the tank. Rest of time off. When putting tanks in the water (shore diving or cave diving)or on a hang line always pressurized and then turn off unless breathing on the unit.

 

[ianr33]

Ditto. In cave/tech diving the cylinder is pressurized only when breathing on the tank.

Thats a good point and makes me think this could cause some confusion.

Any tech diver coming across a hang tank will expect to have to turn it on before using it.
Some recreational dive ops hang a tank at 20 feet. Is it turned on? Yes? No? Maybe?? . Can imagine a panicking diver going for a hang tank,finding it gives no gas, not even thinking about turning it on, and bolting for the surface.
Would be a good thing to clarify on a pre dive briefing

Now,whether hang tanks are a sensible precaution, or a crutch for lack of gas planning is another discussion

 

[Wookie]

Charged and off.

 

[seaducer]

I do the same as Cave Diver, AndrewA and ianr33).

+ whatever number we are up too now...

 

[knowone]

Static gas, pressurized off. Travel gas on.
If you have a water ingestion possibility remove all hoses and accessories and soak-flush in a vinegar hot water solution, dry then service, or use. Remove swivel from spg, syringe with solution then water then blow dry. This cleans out the copper bourdon tube no problem. Spg water destruction occurs slowly when there is an unnoticable leak past the case overpressure plug or hose attachment nut to body o ring or another internal spigot o ring or faceplate o ring.
A BMW service manual once told me not to split brake calipers and to buy new ones. Commercial rebuild kits were readily available.
Things being as they are, you can't roll into a gas station when you run out.
Much fresh water contains salt.

 

[Rick Inman]

As others, stages charged and off. With CCR and bailout, bailout is on.

One other reg to be aware of as a stage reg is the Atomic M1, which has a reverse poppet in the 2nd stage, and is OPEN when the bottle is depressurized. So, what COULD happen is (and trust me, I know it could), you charge the stage, turn off the bottle, but then somehow during the dive the reg loses pressure and water seeps up into the 1st stage. Then, if the water is very cold, when you pressurize the reg, the water freezes in the first stage and the reg fails. I know this for a fact, because it has happened to me. And the reg can fail CLOSED!:shocked2: It took a tech rebuild, then a replacement reg, then a call to the Atomic techs to diagnose the problem. The tech suggested that, if you must use the M1 for a stage reg, that you frequently check the reg during the dive to assure it is pressurized.

BTW, anyone wanna trade an M1 for a MK17?

 

[Wookie]

As others, stages charged and off. With CCR and bailout, bailout is on.

One other reg to be aware of as a stage reg is the Atomic M1, which has a reverse poppet in the 2nd stage, and is OPEN when the bottle is depressurized. So, what COULD happen is (and trust me, I know it could), you charge the stage, turn off the bottle, but then somehow during the dive the reg loses pressure and water seeps up into the 1st stage. Then, if the water is very cold, when you pressurize the reg, the water freezes in the first stage and the reg fails. I know this for a fact, because it has happened to me. And the reg can fail CLOSED!:shocked2: It took a tech rebuild, then a replacement reg, then a call to the Atomic techs to diagnose the problem. The tech suggested that, if you must use the M1 for a stage reg, that you frequently check the reg during the dive to assure it is pressurized.

BTW, anyone wanna trade an M1 for a MK17?

Man, I was born in Spokane. As the proud owner of a couple dozed M1's, I offer this sage advice: Move to where the water doesn't freeze. It's cheaper than buying new regs. You can get rid of that drysuit, too.