Hello!

I am a novice plumber--o.k. I haven't really done any real plumbing yet. BUT---we don't have much money for hiring a plumber, so I thought I would try the Internet.

The Problem:
Hot water heater is fine.
I get hot water throughout whole house, EXCEPT when we go to shower, we have inconsistent temperatures. It starts blazing hot when the singe dial is set at 12 o'clock, but as you shower, it gets cooler and cooler, until you have it all the way to the left and it's just tepid. Meanwhile, the sink still produces blazing hot water.

Sometimes the shower lasts longer if you gently tap the dial to the left as the temperature shifts, but mostly it's getting worse each time. Both upstairs showers (one a stall, one a tub) has the Moen Positemp dials, and the one in the tub started giving out first.

I bought a new cartridge to replace it, but after looking inside, there is no leaking or problems associated with cartridges.


I think it has something to do with the "rough-in positemp pressure balancing valve." Is that something I could replace? Does my 1989 or 90 fixture have that? Is that what is wrong?

Thanks for any advice!

OK lets pull that cartridge to check for debris on the hot side, left. Remove the escutcheon plate and handle. Moen handles are attached 3 different way so if you can't get it off describe tha handle including location of plastic logo plates or little plugs. Once you have the handle and escutcheon off carefully pry up on the clip showing above the valve, above the stamp thar reads HC. Pull the cartrdige , clean and reinstall using a small amount of plumbers grease.let me know if you get hung up anywhere along the line.