Hi there folks, I'm hoping that a few of you pros out there can give me some advice on a plumbing issue: The Problem: My shower has three knobs, with the middle one responsible for turning the shower on and off. When I turn the knob on, the tub faucet leaks with a light stream of water. I couldnt find a forum for three knob systems, and am hoping for some advice on how to go about making this repair. Lastly, I live in a building, and as such, I do not have access/authorization to shut off the main water. Can the repair still be done without shutting off the main? Thank you so much!!!!