Cistern and Buttons

Prior 1993, 9litre or cisterns that held 2 gallons were used for flushing. So in order to try and save water, this volume was reduced initially to 7.5litres and then finally to the amount that is still in use today of 6litres.

WC systems worked by using a “Siphonic valve” fitting, but nowadays there is another design in which a valve lifts allowing the water to flow. Discharging this from the cistern down into the pan, a device is employed that shuts when the most efficient volume of water has been discharged. NW4 Plumbers fit all types of WC suites. The WC cistern is different today than many years ago. The cistern is actually now, quite a modern piece of technology. The water supplied to the cistern used to be controlled by a float operated valve, which as it sat on the water level would lower when flushed and by doing would open the fill valve at the bottom allowing the cistern to fill. Once the float had levelled off with the incoming water the fill would stop.


Flush Buttons.

Two flush buttons are nowadays usually fitted to a cistern, one will carry out a short flush (low volume of water) and the other a long flush (larger volume of water). They use a 2 rod system which release the small and larger volumes of water as required. An NW4 Plumber installs and fixes these buttons.


Siphonic Affect.

When water leaves a tank or cylinder without any help of a mechanical nature is said to have siphonic action. It will travel up and over a tube in the shape of an upside down ‘J’. The long leg joins to the flush pipe whilst the short leg is open to the water in the cistern. When the air inside is taken out, there is a partial vacuum created. This is initiated by a large diaphragm washer lifting and causing a quantity of water to discharge away through the flush pipe taking air and causing a partial vacuum.






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