Moen Brass vs. Plastic Cartridge

Basic Design of Brass Valves

• Moen’s brass valves consist primarily of two components, the valve body and the valve seat. Unlike with cartridge valves, these valve types control hot and cold water separately. It is for this reason that sinks fitted with brass valves feature one handle for cold water and a second handle for hot water. Fitted against the body of the valve are two rubber washers. When the water is turned off, the handle compresses these washers. When the water is turned on, the handle allows these washers to expand and allow water through the valve. The amount of expansion determines the amount of water that flows thought the valve. The valve seat is a threaded circular piece fitted within the faucet housing. The valve body screws into this valve seat.

Basic Design of Cartridge Valves

• Whereas brass faucets feature rubber washers, Moen’s cartridge faucets do not. It is for this reason that cartridge faucets are sometimes referred to as “washerless” faucets. Cartridge faucets do feature a rubber O-ring around the base of the valve to guard against leaks. Cartridge faucets are commonly used for single-handle bathroom sink designs. Unlike brass valves, both cold and hot water flow into the single valve. As the valve is turned via the faucet handle, holes within the valve shift and regulate the water temperature. Cartridge faucets generally require less attention than brass valves and replacing a cartridge usually takes less time than a brass valve.

Repairing or Replacing Brass Valves

• The process of replacing a brass valve is a bit more involved than replacing a cartridge, but the process is still relatively straightforward. Turn the water supply lines located underneath the sink off before disassembling the faucet housing. The faucet handles produced by Moen are held in place with a single set screw. The location of the screw depends on the design. If the handle features a plastic or metal cap, pry the cap off to access the screw. If the handle does not feature a cap, look for a set screw at the base of the handle. Lift the handle off the valve to reveal a large nut. Unscrew the nut to detach the valve body from the seat. Note that one washer surrounds the body of the valve, while the other is held to the bottom of the valve with a screw. Remove the screw to release the washer. Replacing these two washers will most likely stop a water leak, but a very old valve may require replacement. Before installing the valve, coat these two rubber pieces with heat-proof grease. Replace the valve seats with a valve seat wrench if they appear corroded.

Replacing Cartridge Valves

• As with brass valves, the first step here is to turn the water off. This valve design will feature a plastic or metal cap over the center of the handle that hides the handle’s retaining screw. Remove the cap and the screw, then lift the handle off the cartridge. Cartridge valves are typically replaced rather than repaired since finding replacement O-rings can be challenging and because you cannot disassemble the valve if the new O-rings do not stop the leak. Replacement cartridges are produced by Moen and are readily available at home improvement retailers. Slide the new cartridge into place within the faucet housing and reattach the handle.