Is H valve a good replacement for the pony?

[Tassie_Rohan]

With the exception of OOA scenario, is H valve a good replacement for the pony bottle for recreational divers?

H valves are popular with divers (particularly Europeans) who are doing recreational dives in water cold enough that there's a risk of a reg freezing up and free-flowing.

If you are doing dives that require a redundant air source then, as mentioned several times, a pony or set of doubles is the way to go.

 

[String]

Good point.

Have any of you had problems with doubles where you had s to shut things down and it took longer than expected to figure out which valve needed to be off?

If you've got a twinset and cant shut down quickly then you have no redundancy and need to realise that.

Solutions, either invert them to make the valves easier to reach or do what lots of people do and run independent twins without a manifold.

 

[John_B]

Not really an H-valve, but I like my set-up for cold water diving...

I've seen something very similar sold by Beaver Sports in the UK, but they don't export them here in the US due to the lack of a burst disk. I'd love to have a one or two of those for HP130s, even if it meant buying my own compressor to get them filled.

Link to the "Dual Outlet Valve". It's stamped "CE EN 144-1 230BAR M25X2"; does anyone have any idea whether this would fit the "3/4 NPS" tank threads that are standard in the US?

 

[Reg Braithwaite]

One thing to consider about H-valves vs. Y valves is that most H valves have an upgrade path to doubles: You separate the Left and Right valves, put the left on its own tank, buy the manifold and bands, and assemble.

So if you start with two tanks and four valves, you can either go to one set of doubles with an extra pair of valves, add a single tank so you have one pair of doubles and a single with H valve, or buy two more tanks and end up with two sets of doubles so you can do one set of fills for a short expedition.

So for some people, it is not really H-valve vs. doubles so much as H today and doubles tomorrow vs. doubles today and doubles tomorrow.

With a Y valve, that's what it is and what it always will be. It's a specialized item that does what it does as well as it can and that's it.

 

[String]

I've seen something very similar sold by Beaver Sports in the UK, but they don't export them here in the US due to the lack of a burst disk.

Don't think burst disks are even legal here

It's stamped "CE EN 144-1 230BAR M25X2"; does anyone have any idea whether this would fit the "3/4 NPS" tank threads that are standard in the US?

CE EN 144-1 is the EU standard it conforms to. If you're really bored:

The EN 144-1 and -2 series lays down requirements for the insert connector and side ports of cylinder valves. One point to note is that an impact test has been incorporated into EN 144-1. This stipulates that the cylinder valve must not break off completely at an impact strength of 120 joules. This raises safety levels for the user (it is a commonly known fact that there have been problems in the past with handling compressed gas cylinders). The port for compressed air, mixed gases and oxygen stipulated by EN 144-2 will soon result in standardisation of the connections in Europe.

230 bar is the working pressure of the tank (232 bar is standard / 3400psi)

M25X2 is the neck, thread and valve size. This is a metric size and will not work on the imperial sizes used in the US.

 

[John_B]

M25X2 is the neck, thread and valve size. This is a metric size and will not work on the imperial sizes used in the US.

Thanks so much! As always, even if the news is not what I had hoped, its still very helpful to get a knowledgeable answer.

 

[El Orans]

That's a pretty slick valve and reg set you have there - but what is your rationale for needing it?

H valves are popular with divers (particularly Europeans) who are doing recreational dives in water cold enough that there's a risk of a reg freezing up and free-flowing.

Question, meet Answer. Answer, meet Question.

 

[Reg Braithwaite]

H valves are popular with divers (particularly Europeans) who are doing recreational dives in water cold enough that there's a risk of a reg freezing up and free-flowing.

Canada is, of course, fairly European if you are from Nebraska. H-valves are not as common as doubles in Ontario, but a few people dive them in no-overhead environments.

 

[evil_xander]

If you have H or Y valve you need to make sure your shutdowns are VERY fast - you only have 1 tank and it will empty quickly (especially if a problem happens at worse point of dive - just prior to ascent). If the shutdown is slow you'll lose too much gas.

My advice - get a completely redundant air source (so pony or twinset)

This is true. I have a problem doing a shutdown on the Y valve in my drysuit and all due to a bit less mobility of my left arm (not quite the same reach as the right one), so it kinda renders it next to useless basically or difficult, should the need arise.

No such problems with manifolded doubles.

So, if you do choose to go H/Y valve for any reason, make sure you can shut down both valves. Probably it will never happen, but still, if it does, you'll be ever so glad you can.

 

[tomboyy]

I asked my Lds about solo diving and he said a H-valve and a pony were requirements.
didn't mean to hi-jack, but is this a given ?