Need help identifying Grohe Shower valve

[Red950]

Hello,

I'm just a regular person with no plumbing experience but I've been doing DIY repairs at home for simpler stuff.

I have a Grohe Atrio style valve in the shower. The bottom valve controls on/off to the handheld shower head, the top valve controls on/off of the overhead shower.

The temperature valve doesn't adjust temperature, the temperature stays very hot no matter how it's adjusted.

I wonder if the "mixer cartridge" needs maintenance or replacement, but I'm not sure what model the valves are so I can't find any diagrams.

Here are some photos.

Can I safely try to take the mixing cartridge out without turning off the supply to the whole house? I see some videos that can isolate the hot/cold supply to the mixer before servicing but I'm not sure how to do that on this model.

Thank you in advance.

Huge apologies: My original post said the top valve controls on/off of water, and top valve controls diverting between handheld and top shower. This was incorrect. The bottom valve controls on/off of the handheld shower, and the top valve controls on/off of the overhead shower head.

 

[Breplum]

I think 8mm allen wrench will turn off each side of the valve, multi turns of the lower hex, I think the upper hex are the check valves and screens...
Likely 47 662 cartridge, but best to pull first

 

[Sponsor]

 

[Red950]

Hello,

Thanks for this.

I used an 8mm hex key to fully turn the bottom stops for both sides, but when I test the on/off valve above and below the thermostatic valve I still get water flow.

Here are photos of both stops screwed in.