I bought a posi-temp single handle Delta shower facuet and installed it in my upstairs shower. The problem is that there is little hot water coming out. My daughter(with handle all the way over in the red) says that it is way to cold for her to use. I used 3/4" pex as a trunk line to base of shower and branched off 1/2" to shower and sink. Lines are 4 1/2" apart and wrapped in 1/2x5/8 foam. The sink has hot water. I know that I have hot water in the room. So is it the stem or is it all that type of shower facuet has to offer. Thank you Matt B.