Moen Posi-Temp Shower Valve Troubleshooting Guide (6 Fixes!)

If you want to avoid being blasted with hot or cold water when someone flushes the toilet while you shower, a Moen Posi-Temp shower valve is your best bet. However, while it’s an incredible invention, you ought to know Moen Posi-Temp shower valve troubleshooting in case something goes wrong.

The problems you may encounter with a Moen Posi-Temp shower valve include reduced or loss of cold or hot water, leakages, and accumulation of debris and dirt. Other issues include reversed cold/hot sides, low water pressure, and hard-to-turn handle.

Knowing how to fix issues with your Moen Posi-Temp shower valve will save you the trouble of calling a plumber and the cost.

This post will walk you through ways to fix a faulty Moen Posi-Temp shower valve.

Are all Moen Posi Temp valves interchangeable?

Moen Posi-Temp Shower Valve Troubleshooting (Quick Fixes)

If you are in a hurry, go through the table below to learn to fix different issues in your Moen Posi-Temp Shower Valve.

ProblemRecommended Solution
1.No water flowInstall your Moen Posi-Temp shower valve properly
2.Showerhead leakageReplace the Moen Posi-Temp shower valve
3.Water temperature changeAdjust the temperature lever
4.Reversed cold/hot sidesInstall the valve correctly
5.Reduced water pressureClean the valve to get rid of obstacles
6.The handle is hard to turnReplace the cartridge

Moen Posi-Temp Shower Valve Troubleshooting (Causes & Fixes)

The first step in fixing a malfunctioning Moen Posi-Temp shower valve is determining what’s causing it.

1. No Water Flow

What’s the point of having a shower if no water flows through it? If no water flows after installing your Moen Posi-Temp shower valve, you may have installed it wrongly, and you can only solve the issue by reinstalling it.


During installation, insert the shower valve correctly and screw it adequately and tightly. In addition, make sure the handle turns appropriately and get rid of any dirt and debris.

2. Showerhead Leakage

Errors in your Moen Posi-Temp shower valve can cause showerhead leakages which are annoying and could increase your water bill if left unfixed. Therefore, this is an issue you should fix as soon as possible.


Replace your current shower valve with a new one, ensuring you install it correctly. If the problem persists, change the cartridge.

3. Unexpected Change In The Water Temperature

You should be able to shower using water of your desired temperature, whether cold, lukewarm, or scorching hot. Therefore, it’s problematic if the water in your shower changes unexpectedly.

This problem occurs due to issues with the temperature lever in the valve. Typically, this isn’t an issue you would encounter from a new shower valve but occurs after a long period of use.


You can solve this problem and restore the ideal water temperatures in your shower by adjusting the temperature lever. Here’s how to achieve that:

  • Pull out the handle of your Moen Posi-Temp shower valve.
  • Take out the screws using a screwdriver to access the temperature lever (white in color).
  • Pull out the lever’s upper side and adjust it with the other parts to bring the lever to a neutral position.
  • Reassemble the valve and test your shower to see if the problem is resolved.

4. Reversed cold/hot sides

This issue can only occur if you install the cartridge upside down.


Correct the problem by rotating the cartridge stem ensuring the north faces the drain.

5. Reduced Water Pressure

A Moen Posi-Temp shower valve is made to keep the incoming cold or hot water flow balanced even if the water pressure changes because of flushing a toilet or turning on a faucet. While this valve balances the water pressure, your shower valve can develop pressure problems due to clogs.


Inspect your Moen Posi-Temp shower valve for obstacles and get rid of them to restore normal pressure.

Moen Posi-Temp valve installation

6. The Handle Is Hard To Turn

You want a shower with a handle that’s easy to turn, but shower handles can be damaged, clogged, or worn down. Your shower handle can also become hard to turn, and using excessive force to turn it can damage the internal parts of the valve, causing leakages.

The problem with your Moen Posi-Temp shower valve is likely the cartridge is the handle is difficult to turn. Often, debris accumulation in the cartridge causes this kind of issue.


You will need to replace the cartridge to restore the proper functioning of the shower handle. Follow the steps below to do so:

  • Gather the tools you will require to complete the job- pliers, cartridge removal tool, and screwdriver.
  • Turn off the supply line to your bathroom to stop water from flowing to the valves.
  • Pull out the handle from the valve’s grip by unscrewing the screws. Moreover, remove the handle adapter if it’s there.
  • Remove the temperate limit stuff. This step doesn’t require using tools; your hand should do the job.
  • Detach the cartridge from the shower valve using pliers, but make sure you remove the retaining clip first. Don’t be in a rush; take your time.
  • Put in the new cartridge. However, before that, ensure the cartridge’s HC symbol faces up.
  • Reassemble your Moen Posi-Temp shower valve, then test the handle to ensure it’s no longer hard to turn.

How Do You Adjust A Moen Posi-Temp Shower Valve?

Behind a Moen Posi-Temp shower faucet handle is a built-in stop to control how far the handle can go. By controlling the handle’s turning range, the water temperature in a Moen Posi-Temp shower valve cannot get too cold or too hot.

Moen claims that a Moen Posi-Temp shower valve always maintains a steady water temperature of within 3°F as long as the cold and hot pressure operate correctly.

You can adjust your Moen Posi-Temp valve to lengthen or shorten the handle range. Doing so will decrease or increase how cold or hot the water temperature in your shower will get.

Here’s how to adjust your Moen Posi-Temp shower valve.

  • Turn off the supply line to your bathroom.
  • Remove the handle by unscrewing the screws that secure it to the valves.
  • Use a 7/64-inch hex wrench to loosen the adjustment hex screw, then make the turning range shorter or longer by sliding the hex screw upward or downward.
  • Tighten the hex screw and test the water temperature.
  • Put back the shower valve.
Moen Posi Temp shower system issues

How To Replace A Moen Posi-Temp Shower Valve

Your Moen Posi-Temp shower valve will undoubtedly wear off and need to be replaced. Follow this procedure to do so:

  • Shut off your bathroom’s water supply.
  • Turn on the shower valve to ensure all the water in the pipes is drained out to prevent leakages when pulling out the cartridge.
  • Remove the shower handle using a wrench and get rid of the screws with a screwdriver.
  • Remove the temperature limit.
  • Pull out the escutcheon tube.
  • Take out the screws holding the cover plate to remove it.
  • Using regular pliers, pull the clip out, grab the cartridge and twist it back and forth to loosen it up while pulling it towards you. Push it in and out, then continue twisting and pulling until it comes out.
  • Create a hole big enough to install the new shower valve. You can either widen the existing gap or cut an opening on the wall behind the shower valve.
  • Remove the old Moen Posi-Temp shower valve. If the installation involves soldered parts and threaded connections, solder these parts to cut them and detach them from the connectors. Make sure you leave behind a good length of copper to connect the new shower valve.
  • Flush out the valve to get rid of any debris and dirt.
  • Connect the new Moen Posi-Temp shower valve to the connectors.
  • Position the new cartridge the way the old one was installed. Push it to ensure it’s flush with the valve.
  • Put the U-clip back in by sliding it in from the top down, making sure its legs go all the way through.
  • Insert the escutcheon tube back, then turn the water back on to ensure nothing is leaking. In addition, ensure the stem goes from off, cold, to hotter in an anticlockwise direction.
  • Insert the cover plate and screw it in, then reapply the caulk. Don’t overtighten the screws.
  • Put in the temperature limit followed by the handle.
  • Turn the water back on and test your installation to ensure everything works well.

Also, read: Moen Shower Faucet Won’t Turn Off


1. How Do I Fix My Moen Posi Temp Cartridge?

You can fix a faulty Moen Posi-Temp cartridge by replacing it with a new one. Make sure you buy the right cartridge for your shower and follow the installation instructions.

2. Are All Moen Posi Temp Valves The Same?

Moen Posi-Temp valves are temperature-sensitive and have the cartridge facing upside down. In addition, they are designed with a 6.3gpm flow rate.

Final Remarks On Moen Posi-Temp Shower Valve Troubleshooting

Handling your Moen Posi-Temp shower valve with care will ensure it lasts longer, serving you for many years. However, knowing how to diagnose and fix any issues that may arise also goes a long in prolonging its lifespan.

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