Moen provides an online troubleshooting guide for its showers at Moen.com. Available in the website's Support section, the guide offers a comprehensive list of specific symptoms and provides general directions for each repair.
Customers who want a step-by-step tutorial with photographs should also view the article "Moen Shower Pressure Balanced Valve Repair" at About.com, which shows how to replace the cartridge in a Moen brand pressure balanced valve shower. A new cartridge resolves issues with poor water flow, leaks, and handles that are difficult to turn or do not stay in place. The process involves removing the shower handle, handle adapter and handle retaining clip to access the cartridge. In some instances, broken or dirty O-rings on the cartridge may cause the same problems, and customers can replace them inexpensively, avoiding the cost of replacing the entire cartridge.
While Moen customers can fix most problems with a new cartridge, there are some exceptions. Issues with water temperature are often caused by a faulty balancing spool that needs to be replaced. Obstructions in the shower or faucet assembly can cause water to leak from the shower while the tub is running, and customers can sometimes resolve this issue simply by cleaning the shower. Otherwise, they may need to replace the tub spout or shower head.