I'm trying to help an elderly neighbour with their thermostatic shower, an inset thermostatic Grohe model Grohetherm 3000. The 'thermo element' replacement thermostatic insert is expensive, so I want to make sure I understand what is going on before suggesting replacements.
Basically, the thermostatic control is leaking; when the chrome tap cover is removed, there is a black plastic splined 'adjusting nut' (Grohe's description) which screws onto the thermostatic cartridge. There is a small 2mm diameter hole in this part, through which the water is leaking. Is this some sort of air release valve which is letting by? I can't really understand why there is a hole here!
Can anyone explain the function of this hole, and what I should be looking to repair/replace to cure the leak? The shower is working OK otherwise, and is about ten years old, in a pretty hard water area (London).
Thanks in advance.
Basically, the thermostatic control is leaking; when the chrome tap cover is removed, there is a black plastic splined 'adjusting nut' (Grohe's description) which screws onto the thermostatic cartridge. There is a small 2mm diameter hole in this part, through which the water is leaking. Is this some sort of air release valve which is letting by? I can't really understand why there is a hole here!
Can anyone explain the function of this hole, and what I should be looking to repair/replace to cure the leak? The shower is working OK otherwise, and is about ten years old, in a pretty hard water area (London).
Thanks in advance.