I have a double knob system in shower. The hot water knob turns, starts and stops at a point (does not freely spin) but no water comes out. Cold water knob works fine.

Hi UncleJesse...

Something's gotten hung up in there at the valve body. You need to shut the water supply to the valve, remove the handle and then remove the chrome sleeve and flange. Then, you should be able to use a shower valve wrench (see pic.) and remove the stem assembly.

Once the stem assembly is out the culprit should be pretty obvious.

I have attached some pics to assist you with what is probably behind the wall.

Let us know if you want to discuss more...

MARK