Moentrol Valve / Tile Backer Board Question

[Jb9]

Hello,

I am installing my tile backer board over my Moentrol valve and I have the plaster ground in place. What do plumbers like to see as far as access to all the pistons/spools? I know I could just make the hole smaller than my escutcheon but I'm curious if I can make the hole as small as possible without limiting access for a temperature adjustment or other required maintenance.

A big hole that exposes the pistons or a small hole that only encompasses the handle/cartridge?

Thanks

 

[Terry]

Moen has a cover for the valve that stays on until the tile is finished. You will want access to the stops, balancing spool and for where you screw the plate on.
Don't make someone later on have to tap out the tile for access to the valve.