Grohe makes a wide range of appliances and faucets for the kitchen and bathroom of commercial and private homes. Grohe faucets and showers use a replaceable cartridge system that controls the water pressure as well as temperature mixing. You should replace these metal-based cartridges every three to five years as part of routine maintenance. Grohe cartridges use only a single cartridge per appliance. Use name brand or manufacturer provided cartridges as they provide a more secure fit than other cartridges.
Turn off the water main to the room you are working on. It is located under the faucet or shelving unit. The water main can be identified as one or two knobs attached to solid copper piping or flexible metal sheathed tubing. Turn all available knobs half a turn counterclockwise to reach the off position. (See Warnings.)
Use a hex key on the star-shaped aperture located under the spigot or faucet handle. Turn the hex key counterclockwise four to six complete rotations. This will loosen the spigot and handle enough that it may be removed.
Remove the spigot and handle from the faucet assembly to reveal the cartridge system.
Attach your adjustable wrench to the Grohe cartridge, turning it 1/4 turn counterclockwise to unlock it. You may now pull it straight out of the faucet.
Use your adjustable wrench to insert the new cartridge into your faucet, turning it 1/4 turn clockwise until you hear it click into place.
Replace your spigot and handle, locking them into place with the hex key (clockwise).
Grohe cartridges are made of durable materials which you can clean instead of replacing every few years. Soak your cartridge in a mixture of vinegar (10 per cent) and water for at least an hour. Follow this with a light scrubbing with a soft-bristle brush, like a toothbrush, to remove the built-up calcium and lime.
Be very careful when you open up any faucet or bathroom device. These items are in excess of 60 psi of pressure and often very hot, in excess of 37.8 degrees Celsius. Failure to shut off the water main can result in serious injury or burns.