regulator wont go above 12 PSI

I purchased a dual body regulator from keg connection a couple months ago with my 2 keg kit. It has worked fine as I have only been using one side to run a commercial keg which has worked great. I finally got a batch of homebrew finished and kegged it last night. I hooked it up to the gas to start carbonating it and for some reason, no matter how hard I tighten the screws on the body of the regulators I cant get the pressure to go above about 10-12 PSI on either one. On my commercial keg I am serving at a pressure of about 10 psi (5 ft of beer line). I would like to carbonate my homebrew at around 12 PSI for a week or two. Would this have anything to do with me storing the CO2 tank inside the kegerator? Would the cold affect the reading on the regulator gauge so it isn’t actually 12 PSI but much higher? I wouldn’t think that would be the case because if it were much higher, my commercial keg would be pouring much faster and have a lot of foam. When I set it (commercial keg) at 10 PSI it pours nice and smooth so I would think the reading would be about right. The temp in my kegerator is about 38 degrees. I discovered that it wouldn’t go over 12 psi last night when i first hooked it up to the homebrew keg and was trying to crank it up to about 20 psi so I could put a nice blanket of CO2 on the top of the keg and purge all the oxygen but I couldn’t get it to go up that high so I just purged a few times at the 12 psi range. It seemed that there was a good amount of pressure coming out when I purged. There were no leaks that I could see in the keg as I sprayed a bubble solution to check all my connections and the lid so I don’t think that is the case either. i also checked it this morning and the pressure was still holding steady at 11 PSI with no drop in the high pressure guage. Is there a way to tighten down the screws on the regulator more to get a higher PSI? i have tightened them with the screw driver as tight as they will go. any ideas? what am i missing?

Contact Keg Connection. You should be able to crank that regulator up to 20,30,40, etc. without issue and without regard to temperatures. I can easily go from 2 psi to 30 psi on any of mine.

Just to Double check, you've got the nut loose that is attached to the screw?

The regulator adjustment screw has a packing nut on its threaded portion. As Sleepyemt said, this nut needs to be loose.

thanks guys, i will try that.

I know this is an older post, but I just wanted to share the solution that worked for me when I had this exact problem. When I turned the knob on my regulator above 12 PSI, it would just click and wouldn't adjust the pressure. I listened to Sleepyemt and P-J and went to find my regulator adjustment screw. This involved wedging two flat head screw drivers under the knob to pop it off, revealing the screw. When I looked inside the knob, it appeared the plastic was stripped, so could no longer grip the adjuster screw. I'm currently using an allen wrench to turn the screw to adjust my pressure and it works like a charm. I may just keep using the allen because I actually find that easier to use than the knob in the first place.