I have a single handle water valve in the shower that blends the hot and cold water. It has worked fine until recently I have to have it turned all the way to the hot side just to have warm water. Previously, the handle was in the middle for warm water. There are no water heater issues, and all the other sinks in the house have normal hot water. The only change is that I recently had city water installed as opposed to a well. However, there were no major plumbing changes. The hook up was very minor. Does anyone know what the issue could be? Is there some minor adjustment I can do to return it to normal?