Any plumbers out there? I just bought this house and the diverter doesn't work right. If you open it all the way it diverts only half the water to the shower head and the other half to the tub. If closed it diverts all to the tub. i have taken it out and purchased a new one but the same problem. which leads me to believe that the one in there is not the right one. Sooooo...Now what? Is there any way to find out which one is the correct one? Any suggestions? -- besides tearing everthing out and doing it all over.