Rat Blockers

Rat Blockers are designed to stop rats travelling through drains and are installed into pipes within inspection chambers (manholes).

They are usually installed into the drain outlet, but these models can be easily configured to be fitted into a drain inlet.

Rat Blockers allow rats to pass freely downstream, but protect property by preventing their movement upstream. By installing a Rat Blocker into the drain outlet all up stream branches are protected.

Rat Blockers are robust stainless steel devices and are held securely in place with a tight friction fit. Due to their design, these unique Rat Blockers cannot become dislodged into the drainage line.

Source One Environmental supplies two design of rat blocker:  Ratwall from Metex and Nordisk’s TX11.

Ratwall Rat Blocker from Metex

  • Robust, 304 Stainless Steel
  • Reversible flap for installation into either inlet or outfall
  • Opens fully with no hinge within pipe allowing maximum flow
  • Design prevents possibility of unit being lost into drainage line
  • Low cost
  • Award winning
  • Easy installation – unique low force fit
  • Available for DN100 & DN150 pipes
  • Optional 1m & 2m street level installation poles

Installation Instructions

Ratwall installation is easiest when using the optional installation pole.

Remove the cover of the manhole then flush a toilet to inspect the drain operation.

Holding Ratwall in one hand, gently compress the diameter while screwing the installation pole onto the large thread. Screw the installation pole down firmly to hold the body in compression.

Holding the installation pole, Ratwall may now be lowered into position within the manhole chamber and inserted into the pipe in the manner described above.

With Ratwall in place unscrew and remove the installation pole. Test to ensure that the flap is free to move and that it opens in the direction of flow.

Test the drain carefully by flushing the toilet 3 times with toilet paper and visually ensure that the paper and water pass the rat blocker.

Installation without the Installation Pole

Installation without an installation pole may be done by following the steps above and using the supplied nut instead of the installation pole to hold the unit in compression.

Once the Rat Blocker is located in its place in the pipe the nut should be fully loosened using a 17mm spanner.

Installation into Chamber Inlet – Orientation of Flap

Ratwall is factory configured to work within a chamber outlet, but can be re-configured to protect a chamber inlet (with or without installation pole), by undertaking the following steps:

  • Using a 2.5mm Allen Key remove the top brace piece. Remove the pivot pin (or pivot bolt and nut).
  • Rotate the flap by 180 degrees and secure it in place with the pivot pin (or pivot bolt and nut), taking care that it remains free to swing with no resistance.
  • Install the brace in its original position with the two screws.

Fig. 1:  Compression

Tighten nut or use the optional installation pole to compress the body of the unit, for an easy fit

Fig. 2:  Ratwall installation into chamber

Fig. 3:  Benching

Remove Ratwall brace if uneven benching prevents an easy installation

Fig. 4:  Brace Removal

Remove Allen key fixings.  Lift upwards for removal

IMPORTANT NOTE:  The Rat Blocker can be easily removed and re-installed for drain cleaning and maintenance purposes.  Ensure the installation instructions are followed carefully when re-installing the unit.

During installation the warning label should be mounted visibly within the inspection chamber.

During the first three months it is important to check that the Rat Blocker is operating correctly.

The Rat Blocker must be inspected and cleaned at least once a year.  It is recommended that a service agreement is put in place for the inspection and maintenance of the installed Rat Blocker.

TX11 Rat Blocker from Nordisk

  • Professional, industrial-grade rat blocker
  • Over 90,000 units already installed worldwide
  • All parts manufactured in acid resistant 316 stainless steel
  • Features dual serrated flaps
  • Reversible flaps for installation from either the inlet or
    outfall side of the pipework
  • Purpose-made, extendable handle for installation by lowering
    into the manhole
  • Design ensures unit cannot become dislodged and lost
    into drainage line
  • Available for pipes between DN100 & DN300

Installation Instructions

  1. Remove the cover of the manhole chamber then flush a toilet to inspect the drain operation.
  2. Extend the mounting pole to the desired length and attach the Rat Blocker before lowering it into the manhole.
  3. Once the Rat Blocker reaches the bottom, insert it into the desired position by pushing it forward until the stopper of the Blocker is touching the side of the chamber.
  4. Turn the mounting pole clockwise until the desired tightness has been reached.
  5. Remove the mounting pole and test the installation by flushing the toilet 3 times with 6-7 pieces of toilet paper and visually check that the paper and water passes the Rat Blocker.

Orientation of Flaps

All models of the Nordisk TX11 Rat Blocker are supplied with reversible flaps so that the same unit can be used in either inlet or outlet pipes.

Check that the flaps are in the correct orientation before installing the unit. If the flaps are installed in the incorrect orientation this will result in blockage of the drain as the flaps will be prevented from opening. The following images show the correct orientation of the flaps for installation in inlets or outlets (flow direction is indicated by the smaller arrows).

Installation into Drain Inlet

The arrow on the housing of the Rat Blocker and the smaller arrow on the flaps are facing in the opposite direction.

Installation into Drain Outlet

The arrow on the housing of the Rat Blocker and the smaller arrow on the flaps are facing in the same direction.

Adjusting the gap between the flaps and the bottom of the pipe

Before installing the Rat Blocker it is possible to alter the angle of the flap for a better fit into the pipe (if required), this raises the flap by 5mm from the base of the pipe. To do this, install and firmly tighten the two optional hex head (Allen key) screws with retaining washers (supplied). These can be installed on top of the Rat Blocker as shown.

IMPORTANT NOTE:  The Rat Blocker can be easily removed and re-installed for drain cleaning and maintenance purposes. Ensure the installation instructions are followed carefully when re-installing the unit.

The installer’s name and telephone number should be recorded on the installation plate which should be mounted visibly within the inspection chamber. The installer should be contacted to service the unit.

During the first three months it is important to check that the Rat Blocker is operating correctly. The Rat Blocker must be inspected and cleaned at least once a year.

It is recommended that a service agreement is put in place for the inspection and maintenance of the installed Rat Blocker.