Plumbing Fittings Question:

Moen faucets have cartridges that can be replaced. There is a clip (on top) that has to be pulled up and out before the cartridge can be replaced. Often it seems stuck as if it will not come out. Some replacement cartridges provide a plastic square to turn the cartridge in the valve body 1/4 turn. This breaks it free from the valve grease that it is stuck in. If, after replacing the unit ,the hot and cold are reversed, re-install with the cartridge turned 180 degrees.