How to Fix a Grohe Shower Cartridge

Your Grohe shower cartridge might need to be cleaned or replaced if water leaks from the showerhead, tub spout or faucet handles. Odd noises coming from the shower might also be traced back to mineral deposits in the cartridge. If your Grohe shower includes a thermostatic valve or pressure-balancing valve, any malfunction affecting these might also warrant replacing the shower cartridge.

You'll be removing the components that normally hold back the water in the supply pipes, so it's imperative to turn off the water to the shower before you begin. The shower shutoff valve is sometimes inconveniently located within your drywall. In that case, turn off the main water supply to the house before continuing with this project.

Next, you'll need to remove the decorative trim. The flat plate, called an escutcheon, will slide forward as long as there are no faucet handles in the way or visible screws attaching it to the mounting box. Long handles typically twist off when turned counterclockwise, but some may have a setscrew that needs to be loosened with an appropriately sized hex key. Any buttons, such as the one on top of the triple function thermostatic shower's temperature control knob, can be depressed while the escutcheon slides forward.

There may still be another layer of protective materials to remove before the shower cartridge is fully exposed. Remove any visible screws with a Phillips screwdriver or hex key. Slide the second panel forward and set it aside. You should now see the main section of the cartridge and its various valves (or just one valve depending on the model), which have long "necks" sticking out of the rest of the assembly.

You won't know which removal method will work for your shower until you start taking it apart and fiddling with it. At any point you doubt your skills, call a professional plumber. Some Grohe shower cartridges, like those installed with the Rapido Smartbox universal rough-in, can be grasped with an adjustable wrench turned 90 degrees counterclockwise and pulled straight out without too much fuss.

Others, like the GrohSafe 3.0, may require special tools to aid in removal, such as a removal ring (sold with the replacement cartridge) or a spanner socket wrench designed specifically for removing your particular model of Grohe cartridge. For example, when removing the GrohSafe 3.0 shower cartridge, the spanner socket wrench fits over the cartridge to loosen the cartridge nut, which is located within the wall and is awkward to reach with a pipe wrench. Then, the removal ring snaps into a groove below the cartridge. From there, you can unthread the cartridge nut by hand until it is completely off the pipe and then pull the cartridge straight out.

Older Grohe cartridges may be held in place with a large metal bracket, which can be completely removed along with the cartridge by removing its screws. Once this bracket is out, it can be separated from the cartridge by gently tapping the tip of the cartridge with a rubber mallet.