CO2 leak in kegging system

[chesl73]

Hi All

I'm a bit puzzled at the moment and hope someone might have some ideas.
I've a small keg setup, in my small bar fridge I have the CO2 bottle and two 19L cornies.
I've had this setup for between 12 - 18 months and it's been fine.
Two weeks ago I removed the gas bottle from the kegerator to test my new Fermzilla purchase.
After some testing I put the gas bottle back into the kegerator, hooked it up to the the two cornies and after about 2 - 3 days I went to pour myself a beer only to find that the gas bottle was empty.
I went and got a replacement gas bottle and I did a leak test by hooking up to the regulator and the gas lines/disconnects, set it to 15psi and then switched the gas bottle off. I left it like this for 2 days and it still held the 15 psi. I even put the lines etc into some water to check for bubbles but nothing.
So, I put back into the kegerator and attached the two cornies via the disconnects and now after about 2 - 3 days my full gas bottle is empty.....arghhhh!
My initial thought is that maybe the disconnect when attached to the ball valve on the corny has a leak? Given I did the leak test before I hooked it up I'm thinking this is the only thing left. But then why hasn't this been an issue before?
Any thoughts/suggestions would be greatly appreciated.
Thanks

 

[golfandbrew]

Put some soapy water around any connections to test for leaks. If the leak is coming from your posts ,lid or disconnects put some lubricant on the orings or replace them.

 

[zoigl]

I regularly use food grade silicon grease on all my "O" rings, I found this helped prolong the useful life of them.
Sometimes the beer or gas lines develop cracks very near the connections to the keg, these can be irritably hard to detect.