Another carb question

Purge, and reset the psi to your correct psi (probably around 10 psi). Two days may be enough to overcarb, but it shouldn't be too much.

 

It really depends on if it is truly overcarbed.

At 30 psi for 48 hours, I don't think it would be greatly overcarbed. I often do 36 hours at 30 psi, and it definitely isn't overcarbed. Unless you shook it or something, it shouldn't be overcarbed much and if you've purged a couple of times and had the gas off, it should have settled down by now.

If you're getting a ton of foaming in the lines from 48 hours at 30 psi, I suspect short serving lines (ideally, they'd be 10 feet or longer) rather than a true overcarbed beer. Make sure you're trying to pour at 10 psi, after purging when you have turned it down.

Of course, sometimes beer foams from jacking the pressure up and down and turning it off, so sometimes it's just best to purge when needed to get it to equalize to the desired carb level.

 

I've never gone that long at a high pressure, usually 24-36 hours, so it's possible that it is indeed overcarbed. But if you had half beer, it could be a lot worse I guess!

Maybe try keeping it at 8 psi until it equalizes, and see how it goes.