Have a concealed shower with two knobs. One to turn the shower on and off (switches between the main head and the hose) and the other does the temperature. The temperature one had developed a leak so I've removed the knob and the faceplate but can't get the catridge out. I've removed a grub screw from the button and something like a cotter pin from the top but it's stuck fast. I looks like there is a thread so I think I need to unscrew rather than pull it out but there is nowhere to get purchase as my water pipe wrench is chewing up the brass ring. Am I missing anything obvious or any tips to remove? Pictures show what I'm looking at, the one of the bottom shows where the grub screw was.
If it helps anyone who comes across this thread with the same issue, I needed to unscrew it using the two small holes on opposite sides of the cartridge. Drove two think nails through a length of wood the same distance apart as the holes for a makeshift wrench.
That looks similar to the Bristan cartridge I struggled with. There's no alternative but to keep trying to pull it out as it will no doubt be crusted with limescale and the o-rings may have hardened and also lost their grease. I kept at it with various tools and eventually it pulled out a bit and then I was able to get more of a grip on it. I applied a lot of grease to the o-rings on the new cartridge...