Turn off the water system
Before trying to remove the Nivitohandle, turn off the water system in the sink. Next, take a screwdriver and push it underneath the handle cap. This will give you better access to the valve area. It is important to remove any scale or lime deposits that have built up over time.
Once you have removed the cartridge, you should remove the screw holding the handle onto the stem. The handle should rotate smoothly. If you are not able to do this, you can use an Allen wrench to turn the nut counterclockwise and lift the handle off the stem. You may also use a cartridge puller tool or pliers to grip the cartridge. Changing the cartridge in your faucet can be a great way to ensure that it lasts longer. If you don't feel confident doing the job yourself, you can always take it to a home improvement store or plumbing supply shop and buy the replacement parts.
Purchase a faucet repair kit
If you don't have a plumbing professional, you can purchase a faucet repair kit and replace individual parts if needed. Make sure to check the rubber parts carefully, especially the O-rings, washers, and ring-shaped rubber seals. Some parts of the faucet may only need replacement if a single part has broken or is simply worn out. Most faucet manufacturers sell a kit with all the parts you need, so you don't need to buy the whole faucet. If you are unsure if you need to buy duplicate parts, you can always take your old faucet to a hardware store and compare them.
Clean the handle
Another way to fix a jammed faucet is to clean the handle. A corroded handle will make it hard to turn. To clean the handle, you can try using a dry rag. However, make sure to avoid applying too much pressure or you may damage the handle.
If the faucet handle is stubborn, try using a hammer. This will help remove the mineral buildup. After this, you can use a wire brush to remove loose corroded bits. If this doesn't work, use a commercial scale dissolver. You can also try using a brush to remove any rust from the faucet handle.
In case you're dealing with a ball-type faucet, you may need to replace the handle instead of replacing the faucet itself. For this, you might need to apply some penetrating oil. If you're not sure how to do this, you can use a wire brush. However, it is essential to remember that this process is not as easy as it sounds. Make sure you wear protective gloves, as it's easy to damage the faucet handle if you make an incorrect move.
