Toilets in the United States use a flapper to control the flushing process. In the United Kingdom and elsewhere in Europe, the toilet siphon is used. A toilet siphon is triggered when the user presses the handle of the toilet. The siphon carries the waste down the toilet and through the sewage line. Since this is an elemental part of the flushing process, you should replace the toilet siphon as soon as you start to see it malfunctioning.
Turn off the water supply valve on the side or rear of the toilet. Turn the valve off by turning it clockwise until you feel resistance.
Empty the rest of the water in the system by flushing the toilet while the water is turned off. Use a cup or some other device to scoop the rest of the water out of the toilet. Use a towel or sponge to remove any remaining water in the system.
Take the float ball out of the system. This is a small ball that lowers and rises when you flush or when the system is filling. Use your hands to unscrew the float ball from the float ball assembly.
Reach into the cistern and use a pair of pliers to remove the screws and nuts holding the siphon in place. Remove the siphon from the cistern.
Put your new siphon into the cistern so that the screws on the bottom of the siphon poke through the holes in the bottom of the cistern. Use the nuts to secure the siphon into the cistern.
Hook the siphon link to the end of the handle lever. The handle lever will connect to the handle used for flushing the toilet. Replace the float ball by screwing it back into place.
Turn the water back on and allow the system to fill back up. Flush the toilet to make sure the siphon is working properly.