For simple retrofit installation into existing manholes

To prevent foul water flowing back from the blocked sewerage system to flood the property from the inside via toilets, plug holes and waste pipes.


These unique and patented Retrofit Non-Return Valves can be simply pushed in to the existing pipework, whether plastic or clay, at the property’s inspection chamber. The valves can be fitted in minutes and do not require any specialist expertise or equipment.


  • Simple push-fit installation into existing manhole – takes approximately 80% less time to fit than a conventional valve
  • Unobtrusive when installed
  • Two sizes available to suit DN110 and DN160 pipes
  • Products available for clay and plastic pipe systems
  • WRc approved product, Cert. No. PT/314/0111 & tested & approved to BS EN 13654 (applies to NRV4 only)
  • Protects against pests, such as rats and other vermin, as well as backwater
  • Version available with stainless steel rat block cap for improved protection against rodent infestation
Product Code Description
NRV4 100mm Non return valve for  110m Plastic Pipe
NRV4/SS 100mm Non return valve for  110m Plastic Pipe with stainless steel flap
NRV4CLAY 100mm Non return valve for DN100 Clay pipe
NRV4CLAY/SS 100mm Non return valve for DN100 Clay pipe with stainless steel flap
NRV6 150mm Non return valve for 160mm Plastic Pipe