Moen single handle shower leaks when hot water is on
I have a leak in the wall from my shower. The leak is sporadic. I am able to play with the position of the handle (more or less hot water) and I can get it to stop. I was able to narrow it down and determined it only occurs when the hot water is running. I figured it was the cartridge and replaced it. However the leak still occurs.
The shower hardware is MOEN Posi-Temp Pressure Balanced Shower Cartridge model # 1222.
I am hoping not to have to open the wall. What else can I do?