Pressure creeps up

I'm kind of new to kegging and I couldn't find what i was looking for in a search so I'm hoping someone can attach a link or answer my question. I was force carbing and set the psi at 30 for 48 hours, then purge and reset to 12 psi. I came back about 12 hours later and found that my pressure was at 20psi. Purged again reset at 12psi and came back 12 hours later and the pressure was back at 20psi. Why can I not get the pressure to stay at 12psi? Did I overcarb the thing?

Yes, it's probably overcarbed. Just keep purging and eventually it should equalize at 12 psi.

I've been kegging for a few years now and just tried the fast Carb method for the first time. I had pretty good results but I prefer to put it in the fridge and set to 12 psi and give it a week. Don't have to worry about over carbing that way.

Poop. Oh well. Purge and wait, purge and wait. Thanks guys