Moen Posi Temp Valve

[Winger27]

I am installing a Moen shower/tub valve into a rough opening. I got where to install it as far as the depth goes. My question is why do I need to cut a 4 1/2" hole. The center cartridge is all that sticks out through the wall. I'm not using the temp stops and do have access from behind. If needed how do I waterproof around it? Thanks

 

[Terry]

You need a big enough hole to install the valve plate. there are two screws that are at a diangle.
You also need space above the cartridge clip. If you don't have enough height above that, you will never be able to change a leaking cartridge. Too many times I come back after tile and some joker has tiled tightly around the stem. Then it's break out the tile bits and chip away to get some space.

The part that seals, is the plate, which after installation has a bead of caulking around it. There is a little notch at the bottom of the plate. Don't fill that in. That's to prevent whatever water that may get by, a place to safely go.

See how long the clip is? That entire clip needs to be removed.

 

[Sponsor]

 

[Winger27]

So your saying as long as there is access to the cartridge clip the hole serves no other purpose? Is the chalking around the trim plate all I need to seal so water does not get behind my tile?

 

[Terry]

The plate covers the hole. There should never be an issue with that.

 

[hj]

Plates that fit entirely outside the wall do not need a large opening. Some plates recess in to the wall and opening has to be large enough to accept them.