pressure barel

[dcbrookes]

Assuming that the top of the barrel is flat and smooth and that the cap seal is in good condition, the main cause of gas leaks in my experience is the S30 valve emergency pressure release rubber. I have abandoned these and switched to an inlet-only S30 valve with a pressure gauge and a separate industry standard pressure relief valve with a fixed working pressure of 10psi.

 

[Buffers brewery]

I agree 100% @dcbrookes . While I’ve ended up making my own barrel cap I’d recommend binning the S30 valve totally and replacing with corny gas post, pressure gauge and proper pressure relief valve. This is one I made earlier.....

https://www.thehomebrewforum.co.uk/threads/s30-hambleton-bard-connector-alternative.89178/
...but this uses a radiator bleed valve instead of a pressure relief valve. I’d recommend the latter now.