Isolator Manifold Procedures for solo divers in particular

[mannydib]

If one of your second stages is free-flowing you shut down that post, obviously.

but if you have a leak comming from a first stage or from a tank neck o-ring how do you go about identifying where the leak is comming from and shutting it down?

ive heard you can put your hands back there and feel for the leak.
however, that doesnt tell you if its the tank or the reg.
so should you isolate first to ensure you preserve 1/2 your back gas?

has anyone ever had to do this?

 

[Stoo]

If one of your second stages is free-flowing you shut down that post, obviously.

but if you have a leak comming from a first stage or from a tank neck o-ring how do you go about identifying where the leak is comming from and shutting it down?

ive heard you can put your hands back there and feel for the leak.
however, that doesnt tell you if its the tank or the reg.
so should you isolate first to ensure you preserve 1/2 your back gas?

has anyone ever had to do this?

I dive mostly in the Great Lakes, virtually all of my dives are over 100' and many are 150'-180', so freeze-up is a reasonable possibility, although I haven't had a serious problem like that for a long time. I dive with my isolator open just a 1/4 turn or so, so that I can shut it down quickly if necessary... and I practice doing it on most dives. I know guys that dive with it closed when it's really cold and just alternate regs to keep the tank levels equivalent more or less. Personally, when the water is +2C, I like to leave my reg in place, although I sometimes will "feel" my second stage stating to freeze, so I will switch regs to give my primary a chance to "warm up" by flushing some nice "warm" water through it.

The two situations you describe are pretty rare I think... in 30+ years of diving, I don't know first-hand of either happening... but you never know. I would absolutely isolate first, and figure out the problem after insuring my gas supply was safe.

 

[wedivebc]

I dive with 2 spgs so I would just need to look at which one is falling. I dive independant doubles so it's no big deal I just switch regs if one were to stop delivering gas for any reason.

 

[GDI]

If you have any dought and cannot determine which is leaking, a burst disc or valve o-ring then shut down the isolator and once you determine which cylinder has the problem breath that reg (if still functioning) to use what available gas is still there and make your way back up to the surface

 

[mannydib]

I dive with my isolator open just a 1/4 turn or so, so that I can shut it down quickly if necessary...

interesting solution. does it affect the breathability of the regs at all?

 

[Walter]

It will be the regulator. Shut down the reg ASAP. In fact, I've never heard of a tank neck O-ring or burst disk failing at depth. I see no need for the isolator at all.

 

[diverbrian]

It will be the regulator. Shut down the reg ASAP. In fact, I've never heard of a tank neck O-ring or burst disk failing at depth. I see no need for the isolator at all.

I have to look it up, but see Dr. Bill's incident a few years back when he had a failure of his tank valve. Bad things happen, and I don't want to be on a coroner's table because I was the millionth person on something that only happens one in a million times.

Actually, I believe that the isolator valve came about because of cave divers. It is far more easy to have a problem when you are scootering in a cave or trying to squeeze through a restriction.

Seeing that only use one SPG now, I would simply have to say that if I hear air bursting out after I shut the isolator and don't see a pressure drop, I know it's from the the tank to my right. If the pressure is bottoming out, it is to behind my left shoulder. If it is still going after I isolate the reg, then it is a tank valve problem. But, in any case I had better be heading for my first deco stop and looking forward to getting on my deco gas. Or if an NDL dive, looking for the line to start my deep stops and start heading up it is severe enough to even take underwater troubleshooting to this point.

 

[Stoo]

interesting solution. does it affect the breathability of the regs at all?

Not at all. You can't breathe gas as fast as the tanks will equalize...

I see no need for the isolator at all.

I agree that, in theory, an isolator doesn't do anything that shutting down a reg wouldn't do, except in the rare cases mentioned... neck o-ring, burst disk failure etc., all of which I agree are unlikely.

Where we dive, reg freeze-up is a year-round concern below about 70'... the water never gets above 3C or 35F. The advantage of the isolator valve is accessability... it's clear of obstruction and easy to reach. Tank valves are "buried" underneath the first stage and several hoses, and difficult to reach. I can get to my iso valve easily, but I don't think I could shut down a reg (especially on my left side)... Remember too, we are in drysuits and 1/4" mitts or dry-gloves, so we're a lot less "sensitive" touchwise than you warmer water guys... (yes, I'm jealous...)

 

[Walter]

Brian,

Bill's problem was the inability to get air out of the valve, not the valve leaking. If I remember correctly, something blocked the particle tube. It was on a single tank, but had it been on doubles, turning off the isolator would have accomplished nothing but cutting his air supply in half.

 

[Stoo]

Brian,

Bill's problem was the inability to get air out of the valve, not the valve leaking. If I remember correctly, something blocked the particle tube. It was on a single tank, but had it been on doubles, turning off the isolator would have accomplished nothing but cutting his air supply in half.

Not to get off topic, but if there was ever a reason to wear doubles, this is it... As I get older and more frail, I'm thinking of going to twin 19s...