OPW 71SO-4000 Non Vapor-Tight Overfill Valve, 5-Foot Bury Depth, 8-Foot Tank Diameter

OPW 71SO-4000 Non Vapor-Tight Overfill Valve, 5-Foot Bury Depth, 8-Foot Tank Diameter

Item #71SO-4000

The OPW 71SO-4000 non vapor-tight Overfill Prevention Valve is designed to prevent the overfill of underground storage tanks by providing a positive shut-off of product delivery. The shut-off valve is an integral part of the drop tube used for gravity filling. The OPW 71SO allows easy installation (without breaking concrete) and requires no special manholes.

The OPW 71SO-4000 is a non vapor-tight two-stage shut-off valve. When the liquid level rises to about 95% of tank capacity, the valve mechanism is released, closing automatically with the flow. This reduces the flow rate to approximately 5 gpm through a bypass valve. The operator may then stop the filling process and disconnect and drain the delivery hose. As long as the liquid exceeds the 95% level, the valve will close automatically each time delivery is attempted.

If the delivery is not stopped and the liquid rises to about 98% of tank capacity, the bypass valve closes completely. No additional liquid can flow into the tank until the level drops below a reset point.



  • Simple, Easy and Quick Installation – no excavation or special manholes required.
  • Economical – costs a fraction of expensive, complicated and difficult-to-install valves.
  • Furnished Complete – supplied with new upper and lower drop tubes, mounting hardware and thorough instructions for quick job site time.
  • Completely Automatic Operation – no prechecks to perform, no resets and no overrides to be broken or abused.
  • No Pressurization of the Tank – operates directly from liquid level.
  • Retrofits Directly – for both new and existing tanks with 4" fill risers.

Valve Body: Cast aluminum 

Float: Nitrile rubber, closed cell foam 

Valve: Aluminum 

Seals: Viton Upper & lower 

Drop Tube: Aluminum 

Plastic parts: Acetal 

Hardware: Stainless steel

Bury Depth: 5 ft. 

Tank Diameter: 8 ft. 

Upper Tube Length: 60 in. 

Lower Tube Length: 83 in. 

Overall Length: 155-3/4 in. 

Max. Riser Length: 53-1/2 in. 

Max. Nominal Tank Dia.: 96 in. 

Max. Actual Tank Dia.: 107 in. 

Weight: 16 lbs.