Tank Storage for Winter

[Darrel Conger]

A bad cold followed by bad weather had made me miss out on my last local dive of the year. I have a trip to Maui in November but my tanks want be going along on that trip. My question is I have 2 Al 80's and 1 Al 30 Pony bottle that are all topped off. Usually I don't fill them after my last trip and leave about 500 in them. Should I go ahead and bleed off the air down to about 500? Does it may any difference in the life of the tanks. I have everything timed so that all my equipment will be serviced and the tanks getting their viz in early april before the season starts. They are stored inside in a temp controlled closet. Empty or leave them alone?

While I am asking does anyone know how shops handle full bottles brought in for viz. How quickly (or slowly) should they be drained?

 

[letterboy]

I don't see anhy reason to bleed them, just move your schedule back a few weeks and dive them to use the air . . . or do a cold weather dive ;-)

when I worked in a shop if you brought in full tanks we would generally leave them just cracked open at the end of the day to slowly bleed the air out of them. of course I have also just cranked the valves open, caused the valves to form ice . . . probably not great for valves. . .

 

[OldNSalty]

I don't think you are going to harm your tanks at all by keeping them full. For me, I would try and find a dive to do and breath them down but if that isn't possible just let them sit. The shop will drain them to do the vis.

 

[GrumpyOldGuy]

Leave them full, it will not hurt them at all to be stored full. If 2 tanks works for your first dive day of next year, you are set to go. There is nothing bad about diving a tank with an expired vis sticker, only trying to get it refilled at the dive site is a problem.

When you need a vis, they will drain them. The rate of emptying them is pretty much dependent on how much noise they want to put up with.

 

[letterboy]

grump - is there any damage to the valves if they ice up, to the o-rings and such?

 

[Them]

I pretty much go along with Grumpy point for point, and I don't see where any harm would come from either the cold or leaving the tanks full. Maybe if they were steel tanks and you suspected the air from the last fill wasn't really dry, but that's a long shot.

Darrel.... if you take a full tank to ScubaToys (wild guess about where you might go for a viz) they will carry it out front and open it wide. It will scream loud enough to be heard inside the store for a surprisingly long time. That is what I observed anyway. If that bugs you and you can't get out to dive the tanks down, just open the valves at home and toss a blanket over the tanks while they bleed. A blanket, bed sheet, etc. will cut the noise tremendously without slowing the flow particularly.

 

[spectrum]

Leave them, dive them THEN vis them.

Why would you dump full cylinders for the sake of a visual? the visual enables the fill, not the dive.

pete

 

[GrumpyOldGuy]

grump - is there any damage to the valves if they ice up, to the o-rings and such?

No. Think about how many people drive their cars in sub-zero temperature. That valve and tank is an incredibly sturdy piece of gear and a little frost is not going to bother it.

 

[Teller]

There is no damage but when you drain the cylinder rapidly condensation forms. This can flash rust steel cylinders.

 

[GrumpyOldGuy]

There is no damage but when you drain the cylinder rapidly condensation forms. This can flash rust steel cylinders.

A cooling cycle happens every time you dive cold water.
Think about it. If their is any moisture in the cylinder, its already had time to rust which can form with water vapor as well as liquid.
If the air is dry (as its supposed to be), there will not be any condensation inside the cylinder.
As for the outside, it gets wet all the time.