I'm a first time kegger wannabe. Put my american bock extract in the keg. Set pressure at about 11psi as that was what i'd read where it should be for normal, slow carbonation. I was willing to wait. 3 days later, no carbonation. I tried to turn the gas up to approximately 12 psi and learned that i can turn the knob quite a ways before it changes. So, I'm questioning the accuracy of my system. All this reading charts and pressure settings is confusing. Help!