Leaking Corny Key conundrum

[marshbrewer]

I've got a corny that has some kind of odd leak that I can't get my head around. Here is the history.

• came from malt miller pressurised (thus not leaky?)
• used once, thought I had a leak somewhere in my kegerator as I lost a bottle of CO2 keeping it pressurised
• After lots of checks, and just by chance, I was using other cornies and had only found a few minor leaks in my kegorator and fixed them. Came to clean out the 'leaky' corny and realised it was totally unpresurised (it had had the last pint drawn from it then disconnected and left, so it should have been pressurised with gas at serving pressure). Aha, I thought, its a leaky keg, that explains the high gas usage.
• Cleaned it, pressurised it, and used my leak detector spray to look for leaks, None evident anywhere. Left it for a couple of days, and it seemed to hold pressure when empty, just like when it was delivered.
• Sanitised it, filled and primed it (keg conditioning this batch). Pressurised to seal, burped 4 or 5 times and re-pressurised to get rid of oxygen. Pressurised again to 40psi then left in a brew fridge to condition / carb up along with 3 bottles of the same brew . After nearly 2 weeks, bottles were fully carbed. Checked corny - completely no pressure whatsoever.

This is a head scratcher. It just doesn't seem to want to hold pressure when its got liquid in it. Empty, and full of gas, it seems fine. Any ideas?

 

[foxbat]

Sanitised it, filled and primed it (keg conditioning this batch). Pressurised to seal, burped 4 or 5 times and re-pressurised to get rid of oxygen. Pressurised again to 40psi then left in a brew fridge to condition / carb up along with 3 bottles of the same brew . After nearly 2 weeks, bottles were fully carbed. Checked corny - completely no pressure whatsoever.

Left with the gas on or off? If 'off' then your 40psi has dissolved into your beer to carbonate it and that's why you've got no top pressure left.

 

[marshbrewer]

I was naturally carbing @foxbat , so beer + 60g of sugar went it, pressurised to 40psi, depressurised, pressurised to 40psi, etc 4 or 5 times to get rid of air. The finally pressurised to 40psi to seal lid, checked for leaks, then put into fermenting fridge at 25 degrees to carb up (its a Belgian yeast). Apart form the slightly higher carbing temp, thats what I do with all my cornies now rather than force carbing, and has worked on the others?