Grohe Thermostatic Valves

Well,

The previous owner of my house had some pretty expensive taste. He equipped all of the showers with Grohe Thermostatic valves. For those of you who've never seen them, basically they are temperature calibrated valves where you just spin a single knob to the temp you want anywhere from like 70 to 110 degrees and it automagically handles adjusting the hot&cold no matter what the pressure to get your temp (some sort of thermostatic spring).

Anyhow, My brother moved out of my house about 2 years ago. Since then, nobody has been using the spare shower. The spare shower is a nice double-headed shower that is completely tiled in from ceiling to floor in natural stone. I had a friend over recently and he said one side wouldn't turn on at all and the other side was cold only!

Since my parents are going to be spending a few days here next week, I decided I had to look at the shower today. After spending an hour figuring out how to disassemble them, I was able to get the hot water working! The hot side of the valve was completely full of some sort of sludge. With the valve dissembled, I turned the water on (a little bit messy) and all sorts of carbon-like crap shot out into the shower. I cleaned the valve cartridge up in the sink, re-assembled, and Voila, working shower!

Unfortunately, when I tried to do the same to the other side, I ended up breaking the thermostatic valve controls plastic housing. Turns out this side was properly assembled with set screws that were left out of the side I fixed. Unfortunately the set screws are in a spot where they are going to be a nightmare to get to, so I decided I had enough for one day. Atleast it's a nice regular shower again. Once I find a replacement part (so I know I don't have to fix the one I have), I'll just cut the plastic off the brass housing. While I might need to change the other side's cartridge, I'm betting I can fix it just by flushing it out too.

The best news is that I didn't have to jack-hammer out any of the stone!