Grohe Thermostatic Valve Cartridge is stuck!!! Advise please.

[TripTank99]

I am trying to replace thermostatic valve cartridge (Grohe part#47662) in my shower. I cannot get the old one out!!! I have tried to loosen with WD-40 using an adjustible wrench and tapping with a hammer. It is but cant get it to turn at all. It just wont budge. Any tips or advice?

 

[DIYorBust]

I am trying to replace thermostatic valve cartridge (Grohe part#47662) in my shower. I cannot get the old one out!!! I have tried to loosen with WD-40 using an adjustible wrench and tapping with a hammer. It is but cant get it to turn at all. It just wont budge. Any tips or advice?

Is there a set screw you need to loosen before unscrewing the cartridge?

 

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[Marlinman]

The parts sheet is attached below. This takes a 22mm wrench.

 

[Trickysummer]

Hi OP - did you manage to get the job done? I’m now trying to do the same & the brass temperature stop is completely ceased on. How did you manage to free your’s if it was the same part jammed? I’ve WD’d it but no luck. Thinking I may have to get a mini cutter on it!