Choosing A New WC Cistern
Introduction
From antique style high level cisterns to discreet close coupled or concealed models, the choice of WC cistern is so wide that you’re bound to find one to suit your requirements. Before buying, always ensure that the equipment carries the British Standards ‘Kite mark’, or complies with the equivalent EC standard.
Low level cistern
Considered the standard type of cistern till very recently, low level cisterns are sited just above and behind the WC pan. Often made from the same material as the pan, and in the same colour, low level cisterns connect directly to the rear of the pan via a short flush pipe. Inlet and overflow pipes can be fitted to either side of the cistern, the choice of which is often dictated by existing service points are space requirements. The overflow pipe is often fitted to the side nearest to an external wall, as the overflow water simply vacates the system to the outside – often dripping onto the pathway!
- Dimensions: Low level cisterns are on average 455mm wide, 350mm high, and project 230mm from the wall. Larger and smaller sizes are also available.
- If you are replacing your wc suite, bear in mind that external overflow pipes will no longer satisfy current building regulations; your new suite must include an internal overflow mechanism.
High level cistern
Working to the same principle as a low level cistern and often found in very old properties, or Victorian style bathrooms, these cisterns are usually mounted on shelf brackets, high up towards the ceiling c. 6 ft from the floor, and use gravity to carry the water to the pan via a long flush pipe. Due to their lack of popularity these days, high level cisterns are not commonly available from the average bathroom store, however comparable units are frequently to be found at a plumbers merchants.
- Dimensions: High level cisterns are on average 455mm wide, 350mm high, and project 230mm from the wall. Larger and smaller sizes are also available.
Close coupled cistern
Unlike high and low level cisterns, close coupled cisterns are bolted directly to the wc pan thus forming one single integrated unit. Both inlet and overflow connections are made at the base of the cistern, however unlike other types of cistern, an internal standpipe is connected to the overflow connection to allow any water to overflow directly into the pan itself.
- Dimensions: Close coupled cisterns are on average 400mm wide, 410mm high, and project 165mm from the wall. Larger and smaller sizes are also available.
You may also notice close coupled WCs classified as either BSIO or SSIO, this refers to;
- Bottom inlet Supply, Internal Overflow [BSIO]
- Side inlet Supply, Internal Overflow [SSIO]
If using your existing plumbing points, ensure that you purchase the correct WC to fit these.
Space saving cisterns
In a small space, such as a cloakroom, often a regular cistern will not be appropriate. This can be overcome by using a corner cistern or a compact cistern. Pretty much as the name suggests, corner cisterns fit into a corner, and compact cisterns consist of a plastic unit which is usually 4 to 5 inches from front to back. To help conserve space, the majority of space saving cisterns work to a close coupled format rather than the standard 2 separate units.
- Dimensions: Corner cisterns are on average 375mm wide, 355mm high, and project 280mm from the wall.
Concealed cisterns
This is more a style of bathroom rather than a type of cistern, as a concealed format simply consists of a low level cistern hidden behind panelling.
The advantage, driven by the obvious aesthetical nature of the layout, is that a utilitarian basic cistern can be used, which is therefore relatively inexpensive.
The cistern is connected in the same way as standard low level variants, the main difference being that the flush is mounted into the face of the panelling rather than using a flushing lever. If considering this format of WC, remember to allow access for servicing.
- Dimensions: Concealed cisterns are on average 415mm wide, 295mm high, and project 170mm from the wall. Larger and smaller sizes are also available.
Further information and useful links
- Find a Bathroom Showroom near to you
- Find a Bathroom Fitter near you
- Find a Bathroom Fixtures & Fittings supplier near you
- Find a Plumber near you
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