When your Moen sink sprayer is stuck on, the problem is in the control lever or button of the handle. Moen recommends replacing the spray head, and you'll find the same advice on Kohler's website to remedy a similar problem with Kohler sprayers. In fact, it is possible to repair a kitchen faucet stuck on spray mode, so replacing the spray head isn't always your only option.
Hard water deposits can collect in the spray head control in the same way they do inside a faucet valve. The spray control can also stick because it's rusty. Both problems have simple solutions that may or may not require taking apart the spray head.
Solving Kitchen Sink Sprayer Problems
Your sprayer is likely to have scale or rust buildup inside it if the head has a whitish or yellowish glaze, which is the telltale signature of hard water. Among the antidotes for scale and rust are commercial dissolvers, such as CLR, but vinegar is also effective, and you probably already have some. If either scale or rust is the problem, all you need to do is unscrew the sprayer and immerse it overnight in the world's favorite French fry condiment — ketchup.
Although it isn't completely necessary, it's a good idea to turn off the water shutoff valves before you unscrew the sprayer from the hose. Don't forget to clamp the hose so it doesn't disappear underneath the cabinet. Remove any rubber parts, because vinegar degrades them, and soak the sprayer in a bowl large enough to completely immerse it in full-strength vinegar.
Even Easier, Try Spray Lubricant
If your sprayer has a lever, and it's stuck in the down position, you may be able to loosen whatever is holding it by lifting it and spraying lubricant directly on the control rod. Grasp the rod with needle-nose pliers and move it back and forth a few times to distribute the lubricant, then spray a little more. If the lever doesn't start retracting after a few minutes or if your sprayer has a push button, it will probably help to take the spray head apart for a deeper clean, if possible.
Unless your spray head is molded from a single piece of plastic, you should be able to find screws holding its two halves together. Loosen those screws and spray lubricant directly on the control or, if necessary, manually unstick the button.
If you can't take apart the spray head and it has a button, you may be able to unscrew the button so you can unstick the control. If not, you've probably reached the end of the road, and it's back to "Plan A" — replace your lever-style or button-style spray head.
Replacing the Spray Head
You can often find universal spray heads that will fit most faucet models. If you prefer the one you have, you'll need the faucet model so you can order a new spray head from Moen's website or from a third party distributor. You can often find the faucet model number for Moen faucets on a label affixed to one of the faucet supply tubes, which you can find by going underneath the cabinet with a flashlight. If you can't find the model number, take a picture of the faucet and compare it with the models on the Moen site.
To replace the spray head, unscrew the old one by hand or using pliers and screw on the new one. It should only need to be hand tight. If you see an O-ring on the end of the spray hose when you remove the head, it's a good idea to replace it.
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.