When I am using my shower my single handed shower is leaking only cold water. It is leaking into the floor below it, and is not a constant leak. It only happens during water running. When shower is hot the water leaking is cold. I believe it is the Pressure valve but not too sure. Any ways to fix this with ease, long lasting, and relative cost efficient? I will be doing it myself just wondering if any better ideas then replacing whole pressure valve.