The shower diverter valve diverts water from the bathtub faucet to the shower head. A common style of valve has a button located on the front of the faucet that you can pull to engage the diverter, allowing for water to be rerouted. Over time, these valves fail. To replace a shower diverter valve, it’s easiest to simply install a new faucet with a built-in valve.
Step 1 – Remove the Existing Faucet
First, you must remove the existing faucet. There are a couple ways your faucet might be attached.
Faucets Threaded Into the Plumbing Fixture
Some are threaded directly into the plumbing fixture in the wall. In this case, unscrew the whole faucet, just like unscrewing a lid from a jar. If it's hard to move, insert a hammer handle in the mouth of the faucet, and use the extra leverage to twist it out.
Faucets Fastened to the Piping
Other faucets are fastened to the piping with set screws at the base of the faucet, near the wall. In this case, use an appropriate-sized Allen wrench or screwdriver to loosen the screw. Then, pull the faucet out.
Step 2 – Buy a New Faucet
Take the old faucet to a plumbing supply store or home-improvement center, and find a new one that matches. You can change the look of the faucet, as long as the way it attaches to the existing plumbing is identical to the original piece. Make sure the replacement includes a shower-diverter valve.
Step 3 – Install the Replacement Faucet
If the faucet screws in place, wrap the threads with plumber’s tape and then screw the faucet on by hand to position it correctly. If the faucet has a set screw, slide it over the pipe and screw it in place with the screwdriver.
Step 4 – Test Your New Diverter Valve
Test the shower by turning it on and off and watching to see if the diverter valve stays in place. Make sure it does not leak while the shower is on. If it does not, you’ve installed it correctly. If it leaks, fix the valve while keeping some important mistakes to avoid in mind, like turning off the water first.