Grohe manufacturers and supplies many high-end kitchen and bathroom hardware devices, such as sinks, showers and baths. Its designs are often unconventional and appear in fancy hotels and restaurants across the world. Shower heads use a cartridge system to control the flow of water and must be replaced every 3 to 5 years for optimal performance. As a cartridge ages, it builds up lime and other deposits that can pollute the quality of your water as well as reduce pressure in your shower.
Turn off the main water stopcock. In the bathroom this will likely be located under your sink. Look for two knobs that are next to each other and attached to either copper pipes or a flexible metal tube. Turn both knobs counterclockwise at least one half rotation to fully shut them off.
Use your hex keys on the faceplate of the shower to remove it. The faceplate will be located between the hot and cold water knobs and typically in the bath itself. For full showers it may be located higher, near the shower head itself. Always turn the hex key counter clockwise to loosen and remove the faceplate.
Attach your channel locks to the shower cartridge. Hold the cartridge in place through the channel locks with your left hand.
Use your right hand and the hex key to unlock the two shower knobs by turning counterclockwise. The hex key holes will be star shaped and located on either side of the shower cartridge.
Turn the shower cartridge counterclockwise while pulling out of the fixture to remove it.
Replace the old cartridge with your new one. Turning it clockwise to seat it into place, and using the hex keys (clockwise) to lock it tight.
Replace the shower faceplate, and turn the main water knobs (under the sink) back to the "on" position.
You can soak an old shower cartridge in certain cleaners designed to remove calcium and lime deposits (like Formula 409) for an hour and then rinse them off. This will allow you to reuse the old cartridge instead of buying a new one, which can be expensive. This should be done once a year to extend the life of your cartridges almost indefinitely.
Failure to fully shut off the water knobs in step 1 can result in the release of scalding and or high pressure water when you remove the cartridges. This can result in direct bodily injury from the pressure or hot water.