Step 4 · Remove Old Valve Body
From the access panel, identify the old 3-handle valve body. It will have a hot inlet, a cold inlet, and two outlets (one for the tub spout, one for the shower riser). Use a mini tubing cutter to cut the hot and cold copper pipes and the pipe leading up to the showerhead. You may need to remove any screws or straps securing the old valve body to the wall framing. Once all pipes are cut and fasteners are removed, carefully maneuver the old valve assembly out of the wall cavity.