Acecare valve issue…

I think it happens sometimes. My first tank a 3 liter leaked overnight.
I regreased o ring and reinstalled , no problem since. I was filling my
9 liter last night and right around 4500 psi just before I was going to
shut down o ring on hose fitting blew. Replaced and refilled no problem.

Is your valve heavily corroded?

Replaced worn "O" rings on molecular sieve filter caps, lubed with silicone grease, both squeezed out under pressure. Wiped everything down with dry cloth and installed a fresh set of "O" rings, lube-free, all good. Suspect very light film of silicone was left after wipe-down but nothing close to what I'd used before. WM

If a burst disc is part of the Acecare valve, be sure to inspect. WM

shootinsquid said:

No sir, both brand-spanking new.

Click to expand...

That frost ?

There are three things that can cause a sealing o-ring to blow. Sometimes it can be a combination of factors. First cause is using a too soft durometer o-ring like ones that come in an economy priced o-ring kit. A 70 or 90 duro buna o-ring is required. Second cause is a valve that is either not tightened or a valve that is out of round so it isn't completely flat to the tank throat when tightened. I've only seen this once on a cheap import valve. Some are well made, some are not. A quality tank valve should only need a hand tight seal with a proper size o-ring. Third cause is using an incorrect size o-ring. IIRC, on most 6.8 and 9L tanks with U.S. 7/8-14 thread, a 212 o-ring is used. Chinese M18*1.5 tanks use a metric o-ring.

Happened to me as well.
Couple years ago I got the idea to replace the scba valves to DIN 300. Ordered the valves (3) from aliexpress and one by one replaced on the 14 L tanks.
I remember that the original orings were very soft on touch, but oh well, I install them this way.
Of course the very first tank - the soft oring squeezed through the gap when I was almost at the end of the target pressure - very close to 300 bars.
Emptied the tank - from almost 300 bars, replaced the oring with NBR 70, top it up again, and no problems since.
That was couple years ago.
My tinkering, the supplied orings were very soft and under pressure the rubber just got pressed through the gap. Not really a OD size but if you keep the cross section for a heair in a plus side that shall be a safe fit.

By the look of that bulging oring the valve was not tight to the tank. Regardless of duro, if the valve is seated flush there is no room for the oring to bulge out like that.

The other possibility is too thick an oring preventing that flush seal.