I have a KegCo dual regulator. I only have one line hooked up to it now. I just kegged a corny keg of beer and pressurized to 30 psi to seal the lid. Once it was equalized, I turned the psi down to 15 psi (I live at 8000 feet above sea level). For some reason the regulator after a few minutes keep going back up to 30 psi. Anyone have suggestions on this or solutions? I don't want to over carb my beer.