Tank Valve Freeze Up

[nikolaus]

Wondering whether anyone else has had this experience, and what to do to prevent it.

I was diving in Malaysia last week (85 degree water). 30 minutes into a shallow reef dive and at about 40 feet, I noticed I had 1495psi left in the tank. 2 breaths later, I was completely out of air and my dive computer was freaking out (reading 200psi, then quickly down to zero). I made a controlled but rapid ascent. On the surface, we disassembled the equip. and found that the tank valve, as well as my first-stage were caked solid with ICE, thus blocking any air from getting to the regulator.

I assume this has to do with a leak, but wondering how it could happen. Was there water in the tank? If so, could that water have run down into the valve and first stage when I was swiming inverted to look under rocks? I know the expanding air can get very cold right there. Was it just bad luck, or bad gear?

 

[300bar]

You assume you had a leak,I would say you had a tremendous freeflow.
Expanding air does get cold but to freeze up in the tropics.

 

[DandyDon]

Sounds impossible...?

 

[300bar]

Not realy,when we worked on Curacao,we let tanks freeze up a bit to demonstrate to students.
We did have to open the valve all the way and let it blow for a minute.
But we did get ice,lots of ice.

 

[DandyDon]

But in 85 degree water...?

 

[300bar]

We did it on land 35C on the beach in the sun.

 

[openmindOW]

We did it on land 35C on the beach in the sun.

Interesting. 35 degrees Celsius is, I think, 96 degrees Farhenheit.

When was the First Stage in question last serviced?

 

[stevejaz]

Sounds impossible...?

Go get a can of compressed air like you use for electrical components and see how long you can hold the trigger down before it starts getting extremely cold and freezing up

My question is the OP said something about being upside down, if there was any moisture in the tank this would have put it near the valve assembly, add a free flow situation or high rate of flow could this have caused this? Interesting they didn't notice a leak while diving though.

 

[pdelannoy]

There must have been a leak. Some way for a constant expansion (flow of gas). Otherwise, I don't see how regular breathing could have accomplished this in 85 degree water.

 

[TheMadDane]

There must have been a leak. Some way for a constant expansion (flow of gas). Otherwise, I don't see how regular breathing could have accomplished this in 85 degree water.

I agree.