Keg Pressure Rising

I have a 5 gal corny w/ a 20# CO2 tank. Both are stored in a temp control freezer held about 40F. I filled the keg with apfelwine set the regulator to 12# and let it sit. A week later poured a glass. It was way overcarbed. I turned off the gas and bled the keg...set it again at 12#. This time I noticed the regulator had risen to about 25#. I tried again, but I have found that whenever I set the regulator @ 12# it rises to about 25# or so. The apfelwine dispenses extremely foamy.


Do I have a regulator issue? I have had the regulator stored for about 5 years. Do I need to do any maintenance to it?

Could use a good lube job. I don't know much about tehse regs as I have just gotten one and not used it yet, but I know in paintball if you didn't keep your regs lubed and clean your pressure would creep and be inconsistent

The diaphragm in the regulator does not work as well at colder temperatures. What you have to do is set it low when you put it in, then come back in an hour or so and inch it up a little till you hit the pressure you want (I've heard). Me... I have my tank and regs outside the fridge.