Step 4 · Disconnect and Remove Old Valve
With access to the valve, you can now remove it. The valve body is likely soldered to three copper pipes: hot inlet, cold inlet, and the shower riser outlet. Use a tubing cutter to make clean cuts on all three pipes, leaving a few inches of pipe extending from the valve. Have a small bucket and rags ready to catch any residual water. Once the pipes are cut, the valve may also be screwed to a wooden support beam (a stringer) between the studs. Unscrew the valve from this support and remove it from the wall.