A DIN reg rated for 300 bar can be mounted on a 232 bar rated DIN valve as the 300 bar DIN regulator threaded fitting has 7 threads and the female side on the valve will have 5 threads...there will be 2 threads of the regulator fitting exposed as the the fitting will bottom out in the valve.
A 232 bar rated regulator will not screw into a 300 bar DIN valve all the way as the DIN fitting on the reg will only have 5 threads and the valve will have 7...the reg will not thread deep enough into the valve for the captured o-ring to seal against the back of the inside of the valve. This is a safety precaution to keep from attaching a non-high pressure regulator from being damaged by a mounting on a high pressure tank.
Typically the 300 bar DIN valves are thicker and lack the depression for yoke screw to tighten against. The thicker valve usally precludes the yoke from fitting over the valve as yoke regulators are nominally rated for use up to 232 bars. The lack of the depression prevents the reg from being properly secured in the event the yoke will fit over the valve.
The typical valve insert to convert a DIN valve to use with a yoke regulator will have 5 threads...this will bottom out properly on 232 bar rated valve but will be inset too deep if threaded into a 300 bar valve and the yoke will not make contact with it to create a seal.
There are devices such as this to get a yoke reg to work with a 300 bar tank but one should take care not to exceed the pressure rating of the regulator when filling the tank:
Amazon.com : 300 Bar Din To Standard Yoke Adapter : Sports & Outdoors
The yoke adapters that one can screw onto a DIN regulator come in 2 flavors as well....one is 5 threads deep and the other is 7 threads deep. If one has a 300 bar rated DIN reg they can use either, but the shallower 5 thread deep adapter will leave 2 threads of the regulator fitting exposed. The 7 threads deep adapter cannot bue used with a 232 bar rated DIN reg as it will not screw on far enough for the o-ring to seal against the lip at the back of the adapter
(I learned this the hard way since my wife's Aqualung Calypso reg is only rated for 232 bar so the DIN fitting only has 5 threads and the yoke adapter the shop sold me was 7 threads deep...took me a bit to figure out why it wouldn't work, hence why I drink and know these things).
Knowing is half the battle.
Cheers,
-Z
