If your Moen kitchen faucet comes equipped with a sprayer, the valve has a diverter to shut off the water to the spout whenever you're using the sprayer. When this part wears out, you can still use the sprayer, but water will still flow from the spout. This is more of an annoyance than it is a serious problem, and many people simply continue to use the faucet and sprayer without doing any repairs. However, replacing a Moen diverter valve is not a complicated thing to do.
The diverter on a Moen shower faucet works in the same way as a kitchen faucet. If the diverter is built into the valve, you can't replace it without replacing the valve. Don't worry, you probably won't ever have to do that, because a built-in diverter in a Moen shower valve seldom fails. Diverters on the spout can fail, though, and the same is true if your faucet has a Moen diverter stem. Both are fairly easy to replace.
Replacing a Moen Diverter Valve
Moen employs several designs for the diverters it supplies with its faucets, so it's a good idea to check the model number and order the diverter that goes with that model before you remove the old diverter. The two most common diverter styles are a collar that fits around the base of the valve or a button that fits inside it.
Once you have the diverter in hand, you'll be able to match it to what you find inside the valve, and the procedure for replacing it — once you get the spout off — will be self-evident. Start by turning off the water, then remove the faucet handle by unscrewing the set screw with a hex wrench and pulling it off. On some models, you also have to unscrew and remove some other plastic parts before you can remove the spout.
To get the spout off, grasp it firmly and wiggle it as you pull upward. Once it clears the O-rings, it will pop right off to reveal the diverter, which is either a collar that you can lift off or a button that you can pull out of the valve body with needle-nose pliers. Install the new diverter, put the faucet back together and you're done.
Replacing a Moen Diverter Stem
If you have a Moen shower faucet with three handles, the middle handle is the shower diverter, and the actual valve takes the form of a plastic stem with holes in the end that control water flow. The procedure for replacing the diverter stem on a Moen shower valve, as detailed on the Moen website, calls for a screwdriver, socket wrench and needle-nose pliers, and you don't have to turn off the water to do it.
Unscrew and remove the handle, then pull out the stem extension with pliers and remove the escutcheon and the wall tube to expose the diverter bonnet. Unscrew this with a socket wrench, then pull out the diverter using needle-nose pliers. Insert the new diverter, screw on the bonnet and re-assemble the handle to complete the job.
Replacing a Spout Diverter
The spout diverter is that little button on the top or side of the spout that you pull up to get the shower to come on. It's fairly common for the seals on these types of diverter to fail, and because they aren't easy to remove from the spout, you usually have to replace the whole spout.
To remove the spout, turn it counterclockwise with pliers to unscrew it from the spout stem. Replace it by screwing on a new spout. Be sure to wrap the new spout with a rag to protect it from damage before tightening it with pliers or a wrench.
Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker.com.