Fitting The Atkinson Overfill Prevention Valve (GV4000)

Fitting The Atkinson Overfill Prevention Valve (GV4000)

Filstop Valve GV4000

Technical Specification

Min Flow:                50 litre/min

The Atkinson Filstop
The Atkinson Filstop – Overfill Prevention Valve

Max Flow:               580 litre/min

Min Pressure:          0.15 PSI (10 mbar)

Max Pressure:         100 PSI (7 bar)


Note: a 62mm (approx) Diameter hole is required to fit this valve.

The Filstop overfill prevention valve is designed to be fitted vertically on top of the tank where the fuel would reach the Filstop float before any venting system in the tank.

1)       Ensure the storage tank is not fitted with an internal fill pipe.

2)       Remove the 2” nut from the valve

3)       Feed the Filstop assembly from the underside of the 62mm hole through so that the 2” BSP thread is both fully exposed & concentric to the hole. Ensure that the o-ring is touching the underside of the tanks skin.

4)       Fit & secure the locknut in place taking care not to damage the threads. Tighten adequately to ensure firm fit.



1)       Connect Tankers fill hose to valve.

2)       Commence filling.

3)       As the tanks maximum capacity is reached, the Filstop will close the line of delivery to prevent an overfill. If the tank is filled to the point that the Filstop closes, isolate the delivery nozzle to the valve &/or turn off the pump. When the pressure in the delivery hose falls, the Filstop will drain the fuel from the line.

4)       Disconnect filling hose.



This valve will only operate correctly with clean fuel. Any foreign body or particles present in the fuel may cause the valve to fail. Failure caused by contaminant will invalidate warranty.


In the unlikely event of you experiencing trouble with this unit please contact your distributor