£100.79Exc VAT
£83.99 Inc VAT

The product is designed to retrofit in existing 110mm plastic manhole and inspection chambers. It prevents foul water flowing back from the blocked sewerage system to flood the property from inside via toilets, plug holes and waste pipes. This patented and unique Retrofit non return valve can simply be pushed into existing plastic pipework. These valves do not require any specialist expertise or equipment and can be fitted within minutes



Simple push-fit installation into existing manhole -Take 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


  1. When entering manhole adhere to appropriate safety regulations, lift manhole cover carefully as it may be heavy (assistance may be needed), identify drainage flow direction by flushing the toilet, and identify how many pipes are connected from the property. You will need to fit a non-return valve to each flow pipe from the property.
  1. Clean out all incoming pipes to remove any slime etc.
  1. Offer valve body into pipe (without “O” rings) to ensure there are no obstacles within the pipe.
  1. Check that the flap is not impeded by the manhole benching. If so grind or chip away benching so the closes unimpeded onto the main body of the valve. Make good benching if required.
  1. Remove valve from pipe and fit single “O” ring onto shallow end of 1st groove on valve body.
  1. With hinge aligned vertical, offer back into pipe and push in right up to body shoulder or at least past “O” ring. If the valve is a tight fit then leave in place, if however the valve is loose fit then remove and place 2nd “O” ring onto shallow end of the 2nd groove on valve body and re-insert into pipe.
  1. For normal use rotate locking lever clockwise to vertical position
  1. For maintenance use by your local water authority or sewage undertaker: the locking lever can be rotated anti-clockwise until it slots into the hinge and will manually close the valve off. The valve should not be left in this position or water/sewage will back up in the outgoing pipes which will cause internal flooding.

Alternative: (for Extension Sleeve use)

  1. If the manhole pipes are recessed, then the extension sleeve supplied may be required.
  1. To fit extension sleeve simply align sleeve pips with valve body holes/slots and push until pips snap into place. Make sure the non-return valve does not obstruct flow from other pipes. Flow installation steps 3, 4, 5, 6 & 7