Geberit Sigma Concealed Cistern 8cm 6/3L H108, Built in Toilet Cistern, In Wall WC Flush Tank, Dual Flush, Sigma Frame Compatible

This category covers the main parts of a toilet: close coupled, back to wall and wall-hung pans, close coupled and concealed cisterns, and the flush valves, fill valves, flush plates, pan connectors and fixing kits that go with them.

Pan and cistern styles

• Close coupled: the cistern sits directly on the back of the pan to form one suite.
• Back to wall: the pan sits tight against the wall, with the cistern concealed in furniture or a boxed-in duct.
• Wall-hung: the pan is carried on a frame built into the wall, with a concealed cistern worked by a flush plate.
• Raised height: taller pans, often chosen for accessible bathrooms.

Matching parts

Pans and cisterns are usually designed in pairs, so check that a replacement is listed as compatible with the other half. Note whether the cistern is fed from the bottom or the side, and whether the overflow is internal, into the pan, or external. Pan connectors join the pan outlet to the soil pipe and come straight, offset and angled to suit the pipe position. For replacement flush and fill valves, match the cistern's outlet size and flush type, single or dual.

Standards and regulations

In England and Wales, under the Water Supply (Water Fittings) Regulations 1999, a single WC flush must not exceed 6 litres, and every WC cistern inlet needs a servicing valve next to the cistern. Dual flush cisterns of 6/4 and 4/2.6 litres are common. Pans with an integral trap, and close coupled suites, are covered by BS EN 997, and separate flushing cisterns by BS EN 14055.

For toilet seats, see toilet seats, or browse complete toilets.