Scubapro S600 MK25 and HP Steel 3442/236

[Soggy]

Unless using S600/MK25 with yoke 236 bar steel tank is not safe, I'll keep my config the same...

It's fine. I dive a Mk25/S600 yoke on my singles rig.

 

[divinginn]

i have been diving my hp 100 on a yoke with a scubapro mk5,no problems,probably ran through about 20 tanks most at or about 3500 psi,havent even had to change the oring yet,but i had the same worries when i first started using that tank.

 

[Jimmer]

I'm actually a little surprised by the lack of ability to get HP fills as well. My LDS fills the high banks to 5000 PSI and gives you a free air fill next time around if your tank is 100 PSI low. The other 2 shops locally that I deal with fill their banks to 4500 at least, and one of those shops fills fibre wrapped SCBA firefighter tanks to 4500 PSI almost daily.

 

[Hoosier]

It is a kind of "supply and demand" and local diving environment. There are some dive shops that even don't have HP storage bank. Yes, it is in U.S. LOL~~~~

An extra charge for HP tank is also another common practice.


A short fill is one of the reasons why I have my own fill station...

 

[Brewone0to]

Unless using S600/MK25 with yoke 236 bar steel tank is not safe, I'll keep my config the same...

I can't tell you that it is "Safe",because anytime that you have a cylinder pumped up to any pressure beyond it's intended operating pressure, you have willingly increased your personal risk in doing so.
Now all the BS aside,I can tell you that in my experience, It is possible to use this sort of minimal overpressure.
I have a pair of HP100's that have been pumped up to 4200psi on more than one occasion, and I have a very similar set-up for valve/regulator.
(valve is actually only 3300psi):11:
Don't ask who does the fills. {Top Secret}
This has not caused me any problems as of yet,not even an O-ring issue.
I do of course realize that this WILL decrease tank life, and cause increased maintenance to the regulators.
But I have weighed out the risks involved,
and I am willing to deal with the outcome.
But, it sure is nice to hit the water with 240 cf of gas!!

 

[Soggy]

I can't tell you that it is "Safe",because anytime that you have a cylinder pumped up to any pressure beyond it's intended operating pressure, you have willingly increased your personal risk in doing so.

3442 is not an overfill for many tanks, including the ones that the OP is referring to.

His Mk25/S600 will be fine. I wish everyone would stop making post to the contrary.

 

[jefffalcone]

Aquatic Escapes, United Divers...wherever. Most shops in the area will fill them to capacity.

Thanks. I've had trouble getting mine filled passed about 3200. Some shops seem to be under the impression that it is somehow dangerous to fill 3442 valves high enough that they will cool down and still be full. The only way I've gotten to the dive site with over 3400 is if I leave them overnight, and then ask them to top it off when I pick them up. Usually I don't care enough to bother.

 

[CompuDude]

Well, I've never dived in the mid-west nor have I dived much in resort places. I dive primarily in the North East, but even when I was living in central New York and there were only two dive shops within 100 miles, I did not have a problem with fills. There are a lot of places that don't have nitrox, but I've never been somewhere that was incapable of filling a tank to its working pressure. I do not believe that there are dive shops in the US that have not *heard* of a HP tank.

My only point was, that it is not accurate to tell someone that they will *likely* have problems getting a fill in a 3442 tank. Maybe there are places that won't fill them (it seems you have had this experience), but it's certainly not common or the norm, especially in the US.

Just because you've been lucky, doesn't make it not true. It can be tough to get a good fill in SoCal which is truly ironic given the high number of HP steel tanks in service here.

There are a number of places with compressors that have a hard time going much over 3000 psi. And those that do have good compressors often have one of two issues (or both): (1) A moronic policy that does not allow an employee to fill beyond the rated pressure of the tank, meaning you'd best leave your tanks overnight so they have plenty of time to top off after the hot fill cools (and hope they're willing), and/or (2) a store policy of not going over the rated pressure (or sometimes, even TO the rated pressure) so that they reduce wear and tear on their compressor. Good for them, bad for you.

Now, most land-based shops have compressors than CAN go higher than 3500, but often they won't for one of the two reasons above. There are quite a few boats in SoCal, however, that have compressors that won't go above 3000-3300. Hot.

So yes, there are quite a few civilized dive locations right here in the U.S. where getting good HP fills can be a challenge.

For example, if I have a DIN 1st stage and 3 tanks: 1 steel DIN and 2 AL80 yoke for multiple dives that day. Can I easily convert my regulator with the DIN-yoke adapter on the beach during the surface interval? or on the boat? How easy is this conversion?

As others pointed out, it's quite easily to slap on the DIN-yoke adapter and use your Al.80s with your DIN regs. DIN is quite the superior connection, but I'm not sure I'd do this in your situation. Best bet for you is probably:

1) Use your HP tank in Yoke configuration and leave your regs yoke. Done. Just keep o-rings handy, as they do get popped a lot more frequently when used at high pressures. There is no problem using your MK25 in yoke at high pressure, the only potential issue is the o-ring.

OR

2) Convert your regs AND your Al.80s to DIN. It'll cost a little more, but then all of yours tanks and all of your regs will be DIN, which is an outstanding situation to be in. Used DIN valves can be picked up pretty cheaply. And you can always use the DIN-yoke converter on the rare occasion you travel or borrow yoke tanks.

 

[DA Aquamaster]

If the valve on your 3442 psi tank is a convertible DIN/K valve, it is not an issue. These DIN valves are 5 threads deep (rather than 7 threads deep as found on 300 bar DIN valves) and they will have a dimple on the back to keep the yoke screw centered. On these valves either a DIN conection or a yoke connection (with the insert installed in the valve) can be used.

My advice for upgrading an AL 80 is not to upgrade them to 300 bar DIN valves but rather upgrade them with 232 bar DIN/K valves. The cost is about the same and once done the tank can be used with either DIN or yoke regulators so you will not be hurting your resale value.

DIN connections are stronger, but there is also nothign wrong with a yoke connection for recreational diving purposes. Unless you are penetrating wrecks, scootering through caves or connectiing to tanks at 3500 psi or higher, you do not need the stronger DIN connection.

THe popular myth is that a DIN valve uses a fully captured o-ring while a yoke connection does not. That is not true as a yoke valve is also designed so that when tight you have metal to metal contact between yoke and valve fully containing the o-ring. If the yoke or valve faces are badly worn this may not be the case, but the same is true with a DIN valve as well. The differences are that the face of a yoke valve is more prone to damage, while the face of the DIN connection on the regulator is alos more prone to damage. In addition, if you drop a DIN valves tank on the valve, you can bend the female threaded pooirtion of the valve rendering it useless. Similarly if you drop a k-valved tank on it's valve, you can damage the valve face.

So both have strenghs and weaknesses and both require a reasonable degree of care. But unless you are a technical diver and or using tanks at 3500 psi or higher there is no real need for DIN valves. In fact, if you travel life is a lot simpler at most destinations if you have a yoke equipped regulator. And yoke valves are less prone to trapping water where it can then be blown into the tank during a fill.

 

[Luis H]

Both yokes and DIN connections are good connections as long as the parts are in good shape and they are properly installed. Both types of connections have been used for decades.

When it comes to long term durability a DIN connection is not as durable as a yoke. I have used both types of tank connections for over 35 years and in most situations I prefer a yoke connection. It is quicker to connect, it doesn’t hold water on the threads, and you are not constantly threading different parts together.

The constant mating different threaded devices (regulators with different valves, fill whips, fill adapter, etc) can put a lot of wear, on the long run on both the regulator male threads and the valve’s female threads. This is particularly a problem in salt water and/ or sandy, dusty environment.

I have had problems disconnecting a DIN connection after a dive because a few very small grains of blowing sand got on the threads and the tank pressure embedded them into the thread surfaces. When I finally got it apart you could see the damage to the threads.


Also the myth that you can’t blow an O-ring in a DIN connection is not true. I have witness it as recent as two weeks ago.


As mentioned, they both have there pros and cons.