We just replace all the water supply lines in our house with pex and we have all new fixtures. In our bathtub we have a new KOHLER® Fairfax® Rite-Temp® shower valve, shower head and spout. When I turn on the water it comes out the spout like it is suppose to. When the water pressure is increased it starts to come out of the shower head as well. This problem occurs with the spout and shower head on or with just the pipe stubs only. All the parts are new. I flushed the system out before installing fixtures. Could the issue be my water pressure is to strong, If so how do I reduce it?

Thanks,
J.D.