Out of interest is this setup basically the same as a Y-valve? (I admit I don't really understand the difference!) Is the only real reason to use an H-valve the fact that it can be expanded to use with dual tanks?
All about H-valves and Y-valves
- Thread starter cybordolphin
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
Go to the link and click around a bit.. you should see a picture of a manifold, and H-valve and a Y-valve all together. I don't have time to get the link for you.
Basically the Y-valve can only be used as a single tank set up whereas the h-valve set up can be used as a regular valve with the crossover port plugged, or as an H-valve with the extra post installed in the cross-over port, or as part of a doubles set. The H-valve is much more versatile.
Basically the Y-valve can only be used as a single tank set up whereas the h-valve set up can be used as a regular valve with the crossover port plugged, or as an H-valve with the extra post installed in the cross-over port, or as part of a doubles set. The H-valve is much more versatile.
scubafanatic
Contributor
- Messages
- 5,090
- Reaction score
- 910
..... about Y-valves..... I own 2 ( one on my E8-130 and another on my OMS LP 112 ) and will likely buy a couple more soon......also own 2 isolation-manifolded twinsets ( OMS LP 85s and Faber LP 76's).
Kim, you're correct, the main 'advantage' to an H-valve is that it can be expanded to build an isolation manifold......however, aside from that, I believe Y-valves are superior.....so I use Y-valves on my single tanks that I have no intention of 'doubling'.....I much prefer the Y-valve layout, much more streamlined/lower profile than H-valves.....I don't like the way one of the H-valve knobs juts straight up.
A Y-valve is essentially a miniaturized isolation manifold.....the only downside is if you blow a tank O-ring or burst disk you can't ioslate that failure....but that rare an event doesn't keep me awake at night.
Another consideration is the Y-valve outlets are closer together than they are with an H-valve, so you need to confirm you can attach your 2 1st-stages to your Y-valve, as sometimes clearance can be an issue......and that you can route all your HP and LP hoses the way you wish.
Here's a neat link to a Y-valve (with 2 regs/BC attached)....... it will show you how cool Y-valves really are:
http://www.fifthd.com/e-education/productinfo/regconfig.html
Karl
Kim, you're correct, the main 'advantage' to an H-valve is that it can be expanded to build an isolation manifold......however, aside from that, I believe Y-valves are superior.....so I use Y-valves on my single tanks that I have no intention of 'doubling'.....I much prefer the Y-valve layout, much more streamlined/lower profile than H-valves.....I don't like the way one of the H-valve knobs juts straight up.
A Y-valve is essentially a miniaturized isolation manifold.....the only downside is if you blow a tank O-ring or burst disk you can't ioslate that failure....but that rare an event doesn't keep me awake at night.
Another consideration is the Y-valve outlets are closer together than they are with an H-valve, so you need to confirm you can attach your 2 1st-stages to your Y-valve, as sometimes clearance can be an issue......and that you can route all your HP and LP hoses the way you wish.
Here's a neat link to a Y-valve (with 2 regs/BC attached)....... it will show you how cool Y-valves really are:
http://www.fifthd.com/e-education/productinfo/regconfig.html
Karl
The H-valve also has a failure issue that Y-valves don't have - the second valve on an H arrangement is a screw in piece that can (and sometimes does, especially during penetrations) get knocked loose. If that joint opens up there is no way to shut the air flow down and you are going to dump your gas in a hurry if you can't reach back there and tighten it back down again. The Y is a solid piece split to two valves, no failure point there.
The Y maybe harder to reach when in the water to shut down and may also have trouble with the first stages getting in the way of themselves and potentially making hose routing very troublesome.
The H makes it possible to someday add a manifold - I've got a left H and a right H on a couple of LP 120's that I keep thinking masochistic thoughts about doubling up. All I need is a relatively inexpensive isolation manifold and some bands (and a stronger back) and I'll be all set!
The Y maybe harder to reach when in the water to shut down and may also have trouble with the first stages getting in the way of themselves and potentially making hose routing very troublesome.
The H makes it possible to someday add a manifold - I've got a left H and a right H on a couple of LP 120's that I keep thinking masochistic thoughts about doubling up. All I need is a relatively inexpensive isolation manifold and some bands (and a stronger back) and I'll be all set!
Steven... don't you go dying on me... doing penetrations with an H-valve on a single. 
Thanks for the replies. Now a further question! It seems to me that using a Y-valve you would have a safer primary/octopus arrangement if you run basically the octopus from another first stage (therefore as a second primary) - is this a fair assumption? I suppose you could even have an LP hose connected to each first stage which would give even an LP redundancy. Presumably you would be somewhat protected against any of:a freeflow/ an LP hose failure/ a first stage failure. Am I thinking sensibly here - or am I missing something else?
Basically a Y-valve or H-valve give you the same redundancy as a set of doubles with the exception of a very important item... arguably the most important item... two cylinders of gas that can be used by either first stage or isolated in the event of a valve to tank o-ring failure.
Personally I don't use either a Y-vavle or and H-valve... though I could easily put an H-valve on my singles since the valves on them are manifold valves with the cross-over port plugged. I wouldn't have to buy extra regs since I already have a doubles set of regs.
I choose to dive singles as singles with only one valve and one first stage. I like the way they trim out and limit the dives that I do with them to make up for what they lack in redundancy. If I need to go deep or get into deco it will be with doubles.
Personally I don't use either a Y-vavle or and H-valve... though I could easily put an H-valve on my singles since the valves on them are manifold valves with the cross-over port plugged. I wouldn't have to buy extra regs since I already have a doubles set of regs.
I choose to dive singles as singles with only one valve and one first stage. I like the way they trim out and limit the dives that I do with them to make up for what they lack in redundancy. If I need to go deep or get into deco it will be with doubles.
scubafanatic
Contributor
- Messages
- 5,090
- Reaction score
- 910
Hi KimLeece,
....yes, you are on the right track.......on my Y-valves I run my air-integrated dive computer/primary 2nd stage/ back-up BC hose off the 'right-post'.......and I run an SPG /octo/ primary BC hose off the 'left-post'.
I dive a dual-bladder DiveRite Rec Wing......with 2 inflator hoses......so I have redundancy in the event of a 1st stage failure... a 2nd stage failure......a BC bladder puncture.....an inflator failure......or an air-pressure guage failure.
I prefer the Y-valve/single tank combination wherever you want to maximize safety without going to the expense/bulk/weight of a 'real' doubles set-up. Also, in my area there are dive operators that forbid doubles ( like the Flower Gardens off the Texas coast where I'm diving this June 24th--26th) so diving a 'big' single tank with Y-valve is the 'best' option I have.
Karl
....yes, you are on the right track.......on my Y-valves I run my air-integrated dive computer/primary 2nd stage/ back-up BC hose off the 'right-post'.......and I run an SPG /octo/ primary BC hose off the 'left-post'.
I dive a dual-bladder DiveRite Rec Wing......with 2 inflator hoses......so I have redundancy in the event of a 1st stage failure... a 2nd stage failure......a BC bladder puncture.....an inflator failure......or an air-pressure guage failure.
I prefer the Y-valve/single tank combination wherever you want to maximize safety without going to the expense/bulk/weight of a 'real' doubles set-up. Also, in my area there are dive operators that forbid doubles ( like the Flower Gardens off the Texas coast where I'm diving this June 24th--26th) so diving a 'big' single tank with Y-valve is the 'best' option I have.
Karl
Chris P. D.
Guest
Okay i understand now so let me ask you this? If i wanted to get rid of carrying around my 19cu foot pony bottle with it's own separate regs would it be wise to go with the H-Valve if all i want is a complete set of second regs just in case my primary craps out on me? Or just stick with carrying my pony?
What do you mean by *my primary craps out on me*?
Personally I keep my single tank dives within an envelope that allows me enough margin to make a controlled ascent at any point including safety stops with the gas left. This really isn't too hard since I do the deepest portion of the dive first and multilevel my way back up.
For example I had an o-ring let go on a low pressure hose at the second stage. I was at 127' on a single lp72 but since it was at the beginning of the dive I had plenty of gas to make a very controlled ascent with stops. If I were a knucklehead and was at that depth with only 500 psi I would have still made it but it wouldn't have been a slow ascent... and if I had been there long enough for me to take a lp72 down to 500 psi I would not have been a happy camper when I surfaced.
Best bet in my opinion is to keep the gear as simple and streamlined as possible and use wise gas management practices.
Personally I keep my single tank dives within an envelope that allows me enough margin to make a controlled ascent at any point including safety stops with the gas left. This really isn't too hard since I do the deepest portion of the dive first and multilevel my way back up.
For example I had an o-ring let go on a low pressure hose at the second stage. I was at 127' on a single lp72 but since it was at the beginning of the dive I had plenty of gas to make a very controlled ascent with stops. If I were a knucklehead and was at that depth with only 500 psi I would have still made it but it wouldn't have been a slow ascent... and if I had been there long enough for me to take a lp72 down to 500 psi I would not have been a happy camper when I surfaced.
Best bet in my opinion is to keep the gear as simple and streamlined as possible and use wise gas management practices.
Similar threads
