Small Hole in valve

[Errington1506]

Hi
I am new to the diving scene, just completed my Open Water. I have purchased a 15l Faber Cylinder and have noticed a small hole in the top of the Valve which goes through into the thread for the Din Fitting (Hole can be seen in the photo).

I have just got my Aqaualung Kronos regs with Din 1st Stage back from servicing (so O ring is new) and connected these to the cylinder and air was seeping out of the hole. I took the regs off and put them back on again couldn't here air seeping out any longer and tested for leaking in the bath and all seems OK now

Does anyone know what this hole is and should it be there as never saw this on the valves the dive school were using, also have a 12L Faber Cylinder for the wife and there inst this hole on her Valve

 

[tbone1004]

it's a small hole for bleeding off any residual pressure when you start to disconnect the reg, fill whips, etc. If air is coming out of there it's because the o-ring isn't seated properly or has something on it as you have found.
Not all valves have them, but many do. Perfectly normal