SPG starts leaking on the surface

[Chavodel8en]

So I guess you can call this a near miss, bc it happened right before I was going to descend. I had even given the descend signal, when my SPG started bubbling pretty strongly. After a bit, had my buddy shut off my air, I kept my SPG high and dry and we swam back (shore dive at Pt Lobos, Carmel). A helpful, experienced diver looked at my SPG, and she simply tightened it on the hose, and I was actually good to go. I had thought it was a catastrophic failure.

I wanted to report this bc I learned some things -

1) An SPG, high pressure hose leak seems like a big deal (lots of violent bubbles), but I only lost about 200 psi in the 2-3 minutes I was leaking. With all the bubbles I thought I was losing gas quickly. Also, I've lost air quickly from free flows (a LP hose), and I figured a HP hose would drain much quicker. But when I looked at my SPG as it hissed air, the needle wasnt really moving. So I assumed that the SPG was compromised and wasnt reporting correctly (note - I may have been influenced by my previous SPG mis-adventures, detailed in a thread below "OOA right at the end of my safety stop"). Turns out the SPG was still working fine -- I was just losing air very slowly, As the experienced diver explained, the hole in a HP hose is so small, it takes forever to drain air.

If the leak had happened at depth, since I wrongly assessed a catastrophic loss of gas, I hope I wouldnt have panicked. We were planning on going pretty deep on this dive (we ended up doing this dive as the 2nd dive, and went to 90'), so if I panicked and ascended quickly, it could have been a bad scene.

2) So I recently replaced a faulty SPG myself. I looked at videos to do it. I thought I did it correctly. Directions were to screw it on the hose, but not overtighten, I guess I didnt tighten it enough. I note that i did two dives on the SPG a month ago with no problems.

I believe that the SPG and reg are all good. I feared that by shutting off the air, water could enter the hose, so I kept the SPG out of the water. We also ran the leak a bit on dry ground, so I hope that flushed out any water,

After it was fixed, I got two dives on it with no problems, so I think Im good.

 

[Drone076]

Some videos for you. It's in russian but self explanatory.


First - low pressure hose failure. Full tank, 18 meters depth, aluminium tank 11.3 litres. First 45 seconds tank is half empty, 2 minutes 35 seconds to completely empty.


Second - same same but high pressure hose. After 19 minutes there's a 60bar still.

 

[RainPilot]

It takes quite a while for a tank to empty through even a cut HP hose, there are videos on here of tests done. I was quite surprised, when I first saw it, at exactly how much longer it took than a cut LP hose.

I have had bubbling SPG issues quite a few times over the years, I have found that using a tiny bit of lube on the spool, and avoiding turning the SPG once it's pressurised have reduced these quite a lot.

Re-affirms the value of a bubble check while you are still shallow and in a position to fix it up before it results in a cancelled dive.

EDIT: @Drone076 seems to have had the same thought at the same time!

 

[guruboy]

A HP hose leak will drain the tank slowest and at a constant rate regardless of depth.

Take a look in your HP port next time you take the hose off. The hole is tiny.

 

[Neilwood]

One thing I would check is the O ring on the HP hose - is it intact or pitted in any way? If so replace it.

 

[bamafan]

 

[guruboy]

One thing I would check is the O ring on the HP hose - is it intact or pitted in any way? If so replace it.

Do you mean the spool? The leak was between the HP hose and SPG.

 

[Akimbo]

This might help put the problem into perspective and relates to @bamafan's post above:

(Reprinted by permission)
This table appeared in Life Ending Seconds, 3000 to Zero in 72 Seconds, Advanced Diver Magazine by Curt Bowen​

 

[raftingtigger]

His leak was because the SPG unscrewed from the hose as he twisted the SPG to look at it. O-ring (spool) was fine. 2 wrenches and a firm, but not excessive tightening and then a check for leaks sufficed to fix his problem.

When I looked at it the SPG was partially unscrewed.

 

[undrwater]

His leak was because the SPG unscrewed from the hose as he twisted the SPG to look at it. O-ring (spool) was fine. 2 wrenches and a firm, but not excessive tightening and then a check for leaks sufficed to fix his problem.

When I looked at it the SPG was partially unscrewed.

You were the experienced diver, awesome! Any chance there was water ingress into the SPG?