The master bedroom shower works fine, but the other shower upstairs and downstairs won't get hot. The sinks will get hot water. I also noticed that in the master if I turn the handle all the way to hot the water stays on and gets hot, but in the other showers if I turn the handle all the way to hot the water turns off. So I'm thinking maybe the knobs were installed incorrectly, or a pipe problem. Please help. Thanks

The house was built in 2007
The brand of the shower products are Moen

So I'm thinking maybe the knobs were installed incorrectly, If the valves ever worked correctly they were installed correctly. A better answer might be that mineral build up from your water heater, ( minerals will build up if you fail to flush your heater on a regular basis.) Instructions later!
You have trash clogging the inlet ports of the cartridge.
Turn the water off to the vale and remove the handle and chrome stop tube. Pull the copper horseshoe clip and remove the cartridge. Check and clear the inlet ports, Now turn the water back on for a few seconds 5to flush out the supplies and open valve body, Reassemble and test.

For long life and fewer troubles you should keep your heater clear of mineral build-up by FLUSHING NOT DRAINING on a regular schedule.

Attach a hose to the boiler drain at the bottom of the tank. With the pressure on, open the boiler drain and let it run until the water runs clear. You will see a spurt of red,(rust) followed by white or yellow grains,(lime or calcium carbonate). This shouldn't take more then a few minutes.

Do this monthly to keep it clear. Now flush out your hot water lines on ALL fixtures that are affected . Now pull each aerator and clean the screens. Be sure you put them back together the same way you took them out. Don't forget to flush it out every month. Your heater will thank you for it. Hope this helps and thank you for rating my answer,

Tom

Thanks. Ill try that and make sure I flush it regularly if it works. As far as installed correctly; it has never worked, we r the 1st owners of the house.

Please keep me informed of your progress, Good luck, Tom