DIN or yoke regulators?
Regardless whether you use the DIN or yoke system on your scuba regulator, you’ll know that it’s in place to keep the first stage safely connected to the tank valve. It is the O-ring between the valve and the regulator that ensures the actual seal, and how you take take care of it is more important than you may think. Because, in a sense, this connection is the weakest part of your dive equipment. In case it fails the tank will empty very rapidly. Exactly how fast it will empty depends on the size of the tank and the pressure inside it, but it is going to empty uncomfortably fast, quite possibly resulting in an out-of-air situation, if you’re doing normal single-tank recreational diving.
A failure could happen because of a worn O-ring or in case something impacts the valve, possibly occuring when striking the ceiling in a cave or a wreck. Therefore, a valve-system that completely encircles and protects the O-ring is preferable. A yoke regulator, also known as an A-Clamp regulator or an international regulator, is the most common regulator. The system is tried and tested and has been used for a long time. To attach a yoke-style first stage to a tank, a diver fits the metal brace over the tank valve, and then tightens the yoke screw to clamp the first stage firmly in place. With this system the O-ring is slightly exposed and the brace and screw takes up quite a lot of space. Though it’s a minor problem it is worth mentioning, that this causes more water resistance, and more importantly is prone to entanglement.
A DIN (acronym for Deutsche Industrie Norm) regulator first stage has a threaded post that screws into the inside of the tank valve. A DIN regulator’s first stage fits into one side of the tank valve, and no additional metal or braces run behind the tank valve. Therefore, O-ring is protected and the whole system more stream-lined and elegant.
There are two different kinds of DIN regulators and DIN valves: 200 and 300 bar. 300 bar valves are deeper and require a regulator with a longer post with more threads. The difference lies in the amount of pressure the tank valve is rated to withstand. There is not much difference as far as the regulator is concerned because the first few threads of the post do all the work. A 300 bar DIN regulator can be easily used on a 200 bar tank valve, but a 200 bar regulator will not seal properly to a 300 bar tank valve.
Almost all sold regulators can be supplied with a first stage fitted for either DIN or yoke valves. And most are easily converted. If you are the owner of a yoke regulator, you will most likely be able to get it converted.
Many tank valves are easily converted as well. By screwing out the insert with a hex key you make space for the DIN valve. When using the yoke system the O-ring is located on the tank outlet. (Actually there is another one at the back of the valve insert as well – hidden away but still there none the less) Whereas when using the DIN system the o-ring is placed in the regulators first – stage. That’s another benefit of DIN regulators – if you own your own regulator, the O-ring belongs to you, so you can make sure it’s sound and lubricated, whereas you’re at the mercy of the dive shop your rent tanks with, if you’re using the yoke system.
The only valid argument not to go DIN is the risk that you may encounter compatibility issues when traveling abroad. This argument is becoming decreasingly true, as most recreational dive tourist destinations now have tanks that fit both kinds of valves-systems available. You could bring your own yoke adapter- just in case. This could be highly relevant if you are traveling to American dominated areas such as The Caribbean and certain places in Thailand. It may be a good idea to shoot your intended dive operator an email before packing your bags. If you are scuba-diving in the Philippines, most regulators and tanks will be of the yoke system, but more and more tanks come with the removable insert so they can be converted on the fly. Your dive shop will no doubt have the hex keys you need to temporarily remove the insert.
At Marine Conservation Philippines we use tanks with DIN valves, and the add inserts so they are generally used by yoke regulators. This means that if you’re a volunteer and bring your own scuba gear, anything you bring will work fine.