A kitchen mixer tap is a one-handled kitchen faucet. The tap mixes the hot and cold water within the faucet body so you can control the temperature of the water with the single handle. Installing a mixer tap is no different than installing a regular faucet because the mixing of the water occurs within the faucet. If you replace a three-part faucet with a mixer faucet, you may need to cover the holes in the sink with tap covers.
Place the plastic gasket over the faucet hole and lower the deck plate over the gasket, if the mixer tap came with a deck plate. Insert the tubes through the faucet hole and lower the faucet body over the gasket or deck plate.
Push the rubber washer up over the shank of the faucet under the sink, then thread on the locknut. Tighten the locknut with an adjustable wrench. Look up at the tap to make sure the faucet faces the right way.
Connect the hot water connection to the hot water supply line. Tighten the nut at the end of the supply line over the threaded end of the hot water connection pipe. Tighten it by hand first.
Connect the cold water connection to the cold water supply line by tightening the nut of the supply line over the threaded cold water connection. Go back and tighten both nuts with the pliers.
Turn the water valves on, if you had them turned off. Open the kitchen tap to test it.