I have three Kohler Fairfax showers in my home. I have replace the RiteTemp valves in all of them over the ten years I have been in my home because of leaking. They no longer leak but none of them will get the water very hot. In addition, the water pressure coming out of the shower heads is wimpy. In my master bathroom I have a Grohe shower which is like a waterfall in comparison. I have tried to adjust these Kohler valves many times without success. This includes adjusting the red temperature flanges/temperature stops. Any suggestions on increasing the temperature and the pressure?