Cartridge glossary

Cartridge

The replaceable insert inside a single-handle (or each handle of a two-handle) valve that opens, closes and mixes the water. Moen describes its standard cartridges as a sleeve (the outer shell, with ports for hot and cold), a moving stem inside it, and O-rings that seal the sleeve into the valve.

Stem

The part that sticks out of the cartridge and connects to the handle. Older two- and three-handle valves often have separate "stems" instead of cartridges. Retailers use both words loosely.

Spline / broach

The ridged teeth on the end of a stem, and the matching teeth inside the handle. Aftermarket parts are often described by spline or "broach" count (for example "16 pt"). Moen's Roman tub guide also mentions splined stem extensions, short adapters that lengthen the stem.

Escutcheon

The decorative wall plate behind the handle. Moen's chart uses how the escutcheon screws are placed to tell its valve types apart.

Bonnet nut / retainer clip / collar

Whatever holds the cartridge in. Delta Monitor valves use a bonnet nut, Moen 1222/1225 use a clip, and Kohler Rite-Temp uses a metal collar with screws over the mixer cap. It must be back in place before the water goes on.

Pressure-balance (pressure-balancing) valve

A valve that reacts to a sudden pressure drop on the hot or cold side, such as a toilet flush, to keep the shower temperature steady. Delta says its valves keep temperature within ±3.6 °F, and Moen says ±3 °F for its Posi-Temp 82330 series. These valves are certified to ASSE 1016. Replace them only with a matching pressure-balance part.

Thermostatic valve

A valve that controls the water temperature itself, not just the pressure balance. Examples: Moen ExactTemp and Delta TempAssure 17T (RP47201, see the Delta identifier).

Temperature limit stop (rotational limit stop)

An adjustable stop that limits how far the handle turns toward hot. Delta calls it a rotational limit stop, and Pfister's 974-5299 has one built in. Reset it after a cartridge swap.

Posi-Temp (Moen)

Moen's single-handle, rotate-only, pressure-balanced tub/shower valve with no volume control. It takes the 1222 cartridge.

Moentrol (Moen)

Moen's push/pull single-handle valve that's both volume-controlled and pressure-balanced. It takes the 1225. A Moen "Standard" valve also takes the 1225 but isn't pressure-balanced.

Monitor (Delta)

Delta's name for its pressure-balance tub/shower valves and cartridges. "Single function" means temperature only, and "dual function" means separate volume and temperature. Examples: RP19804 and RP46074 (single function), RP46463 (dual function).

MultiChoice (Delta)

Delta's universal rough-in valve (2006 on), which accepts 13/14, 17 or 17T series trims and their cartridges (RP46074 for 13/14, RP46463 for 17).

Rough-in valve / valve body

The brass body plumbed into the wall. The cartridge goes inside it, and the trim (handle and escutcheon) goes on the outside. Pfister stamps its bodies with codes like 0X8 (974-5299) or 0X9 (974-292).

Deep casting

Pfister's term for a valve body version that needs a longer cartridge setup. The 974-5299 comes with a deep-casting adapter (4-1/8 in long with it, 4 in without).

Mixer cap / PBU (Kohler)

On Kohler Rite-Temp valves, the service parts are a mixer cap and a pressure-balancing unit (PBU, also called the regulator) instead of one cartridge. See Kohler cartridges.

Diverter / transfer valve

Sends water to the tub spout or the showerhead (or between several shower devices). On three-handle Moen valves it's the middle handle, and on Moen vertical spas it's a separate "transfer valve" cartridge.

Seats and springs

Small rubber seals and springs behind some cartridges, such as Delta Monitor's RP4993 (used with the RP19804). When they wear, the valve drips even with a new cartridge.