Repairing a Moen Shower Pressure Balanced Valve

A Moen shower valve cartridge contains working parts that can go bad over time, so replacing them can resolve various issues. When a pressure balanced Moen shower valve is either leaking or not balancing the hot and cold water correctly, replacing the cartridge can often fix the problem.

First, shut off the water to the house. Drain any water remaining in the pipes by turning on the faucet in the bathroom sink.

Use an Allen wrench to remove the screw at the bottom of the handle. Block the shower drain with a stopper or rag so the screw doesn't fall down the drain if you happen to drop it.

Take the screw all the way out to get the handle off. With the screw all the way out, simply pull the handle straight out and off.

After removing the handle, you can access the handle adapter and temperature control component of the valve. Unscrew the black plastic handle adapter with a Philips screwdriver and pull it straight out.

Next, pull the two white plastic pieces that make up the temperature limit stop kit straight out. Then take hold of the chrome sleeve and pull it straight out so you can get to the retaining clip that holds the cartridge in place.

Before the cartridge can be removed, you'll need to remove the cartridge retaining clip. Note the location of the clip before removal as it needs to be re-installed the same way when the new cartridge is in place.

To remove the retaining clip, use a pair of needle-nose pliers or a flat screwdriver. Take hold of the top of the clip and pull it straight out.

With the clip removed you can now pull the cartridge out. The Moen cartridge puller makes removing the cartridge a little easier, but it is not required.

If you don’t have a cartridge puller, use the plastic adapter that comes with the new cartridge to remove the cartridge. The plastic piece is attached to the end of the cartridge; turn it from side to side with pliers as you pull out. When the cartridge is partially out, you can then grasp the brass stem with the pliers and pull the cartridge all the way out.

Before installing the new cartridge, look in the valve with a flashlight to make sure it's clean. Remove any debris that may obstruct the installation of the new cartridge.

Lubricate the rubber parts of the new cartridge with silicone grease. Push the cartridge in place, making sure the H/C on the face of the cartridge is on top so the hot is on the left and cold is on the right.

When the cartridge is in place, re-install the cartridge retaining clip. If you have trouble getting the clip into position, try moving the cartridge just a bit by using the plastic cartridge puller or using the Moen cartridge puller. Then put the chrome sleeve back into position.

Note: Do not try to force the clip into position; it should slide in easily.

The set of two white plastic pieces called the temperature limit stop kit, provide a scald guard feature on some Moen shower valves. If you have very hot water and are concerned that kids using that shower may be scalded, the scald guard is a great feature.

The shower valve can set up so that no matter how far the handle is turned to the hot side, it will not go past a certain point so the water will not get too hot.

Setting it up is easy but you may have to try it a few times before you get the temperature where you want it. The water can be on while you set up the scald guard, however, the handle and handle adapter have to be off.

To turn the temperature of the valve down, move the outermost white piece to the right to limit the hot. The number of splines you move will depend on how much you want to restrict the hot water. Set it and try turning the valve on with the handle adapter loosely in place until you get it set where you want. If you want hotter water, move the outermost plastic piece to the left a few splines to increase the temperature.

Note: Be careful when testing the setting of hot water to avoid getting scalded. Turn the hot water on slowly so you can stop when it becomes too hot.

Reassemble the handle in the reverse order. First, install the black handle adapter and tighten with a screwdriver. Make sure the black handle adapter is screwed on tightly before proceeding.

Lastly, put the handle back on and screw it in place with the Allen wrench. Turn the water on and test it to make sure the valve gets cold first, then warmer as your turn the handle further towards the hot.