Direct action WC Cisterns

Most modern WCs are washed down by means of a direct action cistern. Water enters the cistern through a valve, which is opened and closed by the action of a hollow float attached to one end of a rigid arm. As the water rises in the cistern, it lifts the float until the other end of the arm closes the valve and shuts off the supply. South West London Plumbers carry out work on these types of WCs.


Flushing is carried out by depressing a lever, which is linked by wire to a rod attached to a perforated plastic or metal plate at the bottom of an inverted U-bend tube (siphon). As the plate rises, the perforations are sealed by a flexible plastic diaphragm (flap valve), so the plate can displace a body of water over the U-bend to promote a siphoning action. A South West London Plumber fault finds on this equipment. Water pressure behind the diaphragm lifts it, so that the contents of the cistern flow up through the perforations in the plate, over the U-bend and down at the flush pipe. As the water level in the cistern drops, so does the float, thus opening the float valve to refill the cistern.


Servicing Cisterns:

The few problems associated with this type of equipment are easy to solve. A faulty float valve or poorly adjusted float arm will allow water to leak into the cistern until it drips from the overflow pipe that runs to the outside of the house. Slow or noisy filling can often be rectified by replacing the float valve. If the cistern will not flush until the lever is operated several times, the flap valve probably needs replacing. If the flushing lever feels slack, check that the wire link at the end of the flushing arm is intact. When water runs continuously into the pan, check the condition of the washer at the base of the siphon.