Almost every returned shower trim kit comes back for the same reason: the trim was built for a different valve than the one already in the wall. Moen sells trim and valves separately, and the two have to match. Before ordering anything from our tub and shower trim range, it is worth spending five minutes working out which valve platform you have.
The three names mean different things
They are often used interchangeably, which causes most of the confusion. They are not the same kind of thing.
Posi-Temp is a temperature control, not a product line
Posi-Temp is Moen's pressure-balancing mechanism. It keeps the shower at a steady temperature when someone flushes a toilet or starts a washing machine and the cold supply drops. A Posi-Temp valve is a single-handle valve: one lever controls both temperature and volume together.
Posi-Temp valves use the 1222 cartridge. If you have ever replaced the cartridge in your shower and the box said 1222, you have a Posi-Temp valve.
M-PACT is the valve body standard
M-PACT is Moen's common valve platform. The idea is that the brass body stays in the wall permanently, and you can change the trim style — or even the function — years later without opening the wall or re-plumbing. The Moen 2580 rough-in valve we stock is an M-PACT body with Posi-Temp pressure balancing, supplied with the 1222 cartridge and four ports.
So "M-PACT Posi-Temp" is not a contradiction. M-PACT describes the body; Posi-Temp describes how it controls temperature.
M-CORE is the newer platform, and it comes in series
M-CORE is Moen's more recent valve system, and this is where series numbers start to matter. M-CORE trim is sold as 2-Series, 3-Series and 4-Series, and the series is part of what determines fit. Our Align UT4292EP, for example, is a 4-Series thermostatic trim, while other kits in the same range are explicitly listed as designed for M-CORE 3-Series valve systems.
Some M-CORE trim kits also name the exact mixing valve they need. The Arris UTS32003BL trim, for instance, requires the M-CORE U140 mixing valve to complete the installation.
How to work out what you have
In rough order of reliability:
- Find the original paperwork or the model number. If you know the valve model, everything else follows. Our guide to finding a Moen model number covers where to look.
- Check the cartridge. If a 1222 cartridge has ever been fitted, it is a Posi-Temp valve.
- Count the handles and what they do. A single handle that controls temperature and flow together points to Posi-Temp. Separate volume control, or a dedicated thermostatic dial, points to an M-CORE 3-Series or 4-Series setup.
- Consider the age of the installation. M-CORE is the newer system. A shower installed many years ago is far more likely to be Posi-Temp on an M-PACT body.
- Take the trim off. With the water shut off, removing the handle and escutcheon exposes the valve body, which usually carries markings.
Do not guess
If you cannot confirm the platform, do not order on the balance of probability. Posi-Temp and M-CORE trim are not interchangeable, and within M-CORE the series matters too. Every listing in our trim kit range states the valve platform and series it is built for, and our valves and rough-in section lists the valve bodies themselves.
If you are still unsure after checking, send us the model number or a photo of the valve and we will tell you what fits.