Rectangular Syphons

The rectangular syphon - also known as a flap valve or diaphragm syphon - is the internal mechanism of a traditional close-coupled toilet cistern that creates the siphonic flush action when the lever is operated. At the DIY Hardware Store, our rectangular syphon and ball valve range covers the cistern components used in standard UK domestic toilet maintenance and repair.

A toilet that runs continuously, fails to flush powerfully, or takes an excessively long time to refill typically has a faulty syphon or fill valve (ball valve). The rectangular syphon creates the flush by lifting its internal flap valve, generating a siphonic action that empties the cistern rapidly into the pan. When the syphon diaphragm wears or tears, the flush becomes weak or fails entirely - a straightforward repair with the correct replacement syphon.

The fill valve (ball valve or float valve) controls cistern refilling after a flush. Available in traditional float-arm and modern quiet-fill formats, in the sizes suited to standard UK close-coupled and low-level cisterns at the DIY Hardware Store.

  • Rectangular syphon flap valves for standard cistern flush mechanism
  • Repairs weak or failed flush without replacing the cistern
  • Ball valves and fill valves for cistern refill control
  • Traditional float-arm and modern quiet-fill formats
  • Suitable for standard UK close-coupled and low-level cisterns
  • Essential components for toilet maintenance and repair