The valve on my tub/shower broke. How do I repair it?
First, decide if you want to tackle this one yourself for the cost of parts and probably several trips to the plumbing supply store, or just hire a plumber for about $125. I’m assuming you’ve probably just got a valve cartridge that’s malfunctioning (that’s most common). If you’re going to do it yourself, shut off the valves that supply water to the tub and shower. Then, turn the tub and shower valve to the on position to make sure it’s no longer under water pressure. Leave it partially open to make the valve removal easier later. Remove the set screw that holds the handle to the tip of the valve stem, wiggle the handle off of the spline, and remove the trim ring. Save any rubber gaskets that seal it to the face of the tile. You’ll probably see either a spark plug-shaped cartridge that is screwed into a cast valve body, or maybe a series of set screws that hold the valve to the face of the body. CAUTION: If you can’t get a nice firm grip on the cartridge with a proper wrench that won’t strip the soft brass, you may need to run to the store to buy a special wrench. Remove and save all the parts, and take them all to the parts counter at a plumbers supply store, where they will match your bag of old stuff to replacement parts. Get a little tin of plumbers grease while you’re there to lubricate all the new stuff as you install everything in the reverse order that you took it out. NOTE: check the water temperature with a meat probe from your kitchen to make sure your max hot water temp from the tub spout is no more than 120 degrees. Depending on the style of valve you have, there may be an adjustment on the valve itself, or you may need to adjust the max temperature at the water heater. After you turn the valves back on and check for leaks, reinstall the trim ring and caulk around the top ¾ of the ring with clear silicone so shower water doesn’t sneak into the wall.