Inspect Defender Series OPV® Without Removal From the Tank

The magnetically-coupled actuator system along with a testing tool allows for primary functionality testing of the Defender Series® overfill prevention valve (OPV) without having to remove the assembly from the riser. Use the following procedures to carry out Defender Series® OPV inspection.


To identify that you are inspecting a Defender Series® OPV, use these distinguishing visual indicators without removing the drop tube assembly.

  1. Locate the name plate which should be affixed to the fill point within the spill container.
  2. Use an appropriate light source, such as an explosion proof flash light, to illuminate the drop tube – identify the black color and 5 stick deflector ribs.

Operational Inspection

The operational functionality of a Defender Series® OPV can be done easily from grade without having to remove the drop tube assembly using the collapsible 11’ (3,353mm) remote testing tool shown below (P/N 708534901).

  1. Insert the remote test tool into the drop tube. You should feel a “pull” when the magnets are positioned correctly and attract.
  2. Slowly raise the remote test tool about 1 ½” (38mm) and you should see the flapper move into the flow path.
  3. If the flapper is observed moving back and forth, the valve is functioning normally.

Installation Inspection

You can verify the correct installation of a Defender Series® OPV at 95% level without having to remove the drop tube assembly using the measurements and the calculation worksheet in the Tech Update PDF.

View or download a copy of the Tech Update Defender Series Overfill Prevention Valve Inspection Without Removal From Tank here.