K valve in a HP120?

[Tortuga Roja]

I've been searching til my head is spinning and can't nail down an answer. Please help.

I just purchased a Faber HP120 steel tank (with a DIN valve) that I want to use with nitrox while diving from my kayak. I have a couple of aluminum 80's With K valves that I will continue to use with cheap air for shore dives. My 1st stage is a Scuba Pro MK20 ultra lite set up for a K valve.

The guy at the LDS gave me a brass adaptor fitting like he uses to fill the tanks. This really doesn't work very well because when screwed into the DIN valve, it ends up aiming in a poor direction for my hoses. It also just doesn't "feel" like right thing I should be using.

Is there a reason I can't put a K valve on this tank?
Is there an adptor that is better suited for this situation?

I guess I want to know the best set up for what I am trying to do.

TIA

 

[simbrooks]

I am not an expert on these matters, but i just throw some stuff out there - i assume this is a HP rated tank and therefore the neck diameter is 7/8" (IIRC), whereas most K-valves on AL80's and the new E-series PST's are 3/4" neck diameters. That would explain why you cant put a regular K on there. I dont know if there are 232bar DIN valves with a 7/8" neck that you might be able to put in with an adapter, i have only seen these in 3/4". Putting the whip filling adapter in there does not sound like a real alternative and could be a recipe for disaster not only in hose routing, but 1st stage placement, potential breakage/air release etc. I am not even sure if they seal that tightly without some escape during filling.

The real alternative is to get your regs converted to DIN and buy a yoke adapter, shouldnt cost more than about $50-80 for both things to be done, most of that is tech time to swap out the yoke to DIN fittings on your 1st stage. Or else sell the tank and get something else.

 

[bcsean]

I wouldn't be diving with the fill adaptor. Changing a valve on a tank isn't a big deal, and finding them shouldn't be that hard. The new pst tanks have 232bar thermo valves with donuts in them, so you can use them for yoke or din.

 

[simbrooks]

Changing a valve on a tank isn't a big deal, and finding them shouldn't be that hard. The new pst tanks have 232bar thermo valves with donuts in them, so you can use them for yoke or din.

But those 232's are 3/4" necks, what other size valves come in 7/8"?

I continue with the thought - why dive yoke on a steel....

 

[Jim Baldwin]

I've been searching til my head is spinning and can't nail down an answer. Please help.

I just purchased a Faber HP120 steel tank (with a DIN valve) that I want to use with nitrox while diving from my kayak. I have a couple of aluminum 80's With K valves that I will continue to use with cheap air for shore dives. My 1st stage is a Scuba Pro MK20 ultra lite set up for a K valve.

The guy at the LDS gave me a brass adaptor fitting like he uses to fill the tanks. This really doesn't work very well because when screwed into the DIN valve, it ends up aiming in a poor direction for my hoses. It also just doesn't "feel" like right thing I should be using.

Is there a reason I can't put a K valve on this tank?
Is there an adptor that is better suited for this situation?

I guess I want to know the best set up for what I am trying to do.

TIA,

Here's my suggestion. Purchase a DIN fitting for your MK 20. This will allow you to dive with the HP tank that you have. You are not suppose to use the fill adaptor for diving.

Next, purchase a DIN adpater that will screw onto your DIN regulator. This will now convert the regulator back to yoke.

I dive DIN with all my tanks. When I travel I carry a DIN adapter and this allows me to use AL tanks with yoke valve.

It will cost you about $100-$150 for the two pieces.

Jim

 

[Tom Winters]

First off, make sure you have true DIN valve on your HP120. That's the deep 300-bar DIN thread and not the shallower 232-bar DIN thread that commonly takes screw-in yoke inserts. If you have the shallower type, just get the inserts.
Failing that, your options are to get a K-valve for the HP tank (BAD IDEA - yoke-equipped regulators are designed for 3000psi max service)
Or retrofit a DIN conversion kit on your Scubapro 1st stage and convert your aluminum tanks to 232-bar DIN valves. Get some used ones and sell your yoke valves on eBay.
Once you start using DIN, you're gonna wind up converting everything anyway - this is a good time to start.
Do not use that little brass fill adapter underwater. It's designed for shop use, not as an integral part of your underwater life support system.

 

[simbrooks]

Next, purchase a DIN adpater that will screw onto your DIN regulator. This will now convert the regulator back to yoke.

I dive DIN with all my tanks. When I travel I carry a DIN adapter and this allows me to use AL tanks with yoke valve.

Just to clarify - yoke adapter. It adapts your DIN reg to a yoke valve. I think i have seen DIN adapters that are used on yoke regs, and i dont mean the little inserts that go in the newer 232bar valves, very convoluted, not an efficient solution.

It will cost you about $100-$150 for the two pieces.

I bought my DIN-yoke adapter for $20, the kit for DIN is not all that pricey, like i said about $40-50 hopefully including installation i believe i was quoted once.

As mentioned in passing above - If you go DIN you are going to want a yoke adapter for those tropical vacations where all you have available are yoke K valve AL80's.

 

[Tortuga Roja]

Thanks to everyone for helping me solve my problem. I just had my reg rtrofitted for DIN and got a yoke adapter. I'm ready to go!

BTW, total cost was $140. $70 + $70 no labor. Keep in mind I live on Maui and everything is high.

 

[The Chairman]

SimBrooks is spot on and it all has to do with the good ol' DOT. The DOT has determined that 232 bar is the limit for the K-Valve (not 3000 psi).

I all gets back to early reg design. The HP seats just couldn't take much abuse. In fact the first ones were designed around tanks that only held 2250 psi. As we got greedier for more air, the pressures started to rise. When 3000 regs and tanks came out, everyone was fretting that this was way too high, and that we wouldn't be able to get them filled (sorta what we heard about 3500 psi tanks). Low and behold, the seats held and shops could fill the tanks.

Din valves were introduced to us for use with tanks that were rated 3500 and higher. But what about those guys who dive with 3500 AND 3000 psi tanks? Well, ScubaPro came out with the "Sport DIN" which was far shorter and anabled the insert that allowed the K/DIN valve hybrid.

There is a myth that the "full DIN" is far stronger than the "sport DIN", but I have to point out that there is NO accident that has ever been documented due to their use. In fact, ask any engineer and they will tell you that a screw achieves 98% holding power with only 3 threads. The only real benefit is psychological.

 

[simbrooks]

There is a myth that the "full DIN" is far stronger than the "sport DIN", but I have to point out that there is NO accident that has ever been documented due to their use. In fact, ask any engineer and they will tell you that a screw achieves 98% holding power with only 3 threads. The only real benefit is psychological.

It may not be stronger or safer, but if the valve or 1st stage doesnt fit the hole it isnt going to work.