Overfill Prevention Valves

Model 71

The Model 71 provides a mechanical method of automatic fuel oil shut-off to prevent overfilling of underground storage tanks during a gravity filled delivery.  It is designed to satisfy EPA regulations covering overfill protection, “a device that will automatically shut off the flow of oil into the tank when the tank is no more than 95% full.”*  It is recommended for installation in conjunction with a Preferred Fil-A-Larm System, which provides a pre-alert audible/visual alarm and shut-off notification to the fill operator, prior to the actuation of the Model 71.

The Model 71 is for use on underground Diesel or No. 2 fuel oil storage tanks when the tank is gravity filled (i.e. not  applicable to “pumped-in fill” applications).  The Overfill Prevention Valve includes upper and lower drop tube sections.  The upper section is flared, rests on the top of a 4" fill pipe, and is secured in place by the tight fill adaptor.  The lower drop tube section extends into the tank and is cut off at either 6 inches from the tank bottom, or at the dimension required by local codes.  The Overfill Prevention Valve is installed between the drop tube sections.  The valve can be installed from outside the tank without excavation (installation is as easy as changing drop tubes).

Caution: On existing tanks, the drop tube may be held in the tank coupling below the riser pipe.  On these installations, the existing drop tube must be removed to accommodate valve operation.

Operation: The Overfill Prevention Valve is a float operated, two stage shut-off valve system.  It is installed as an integral part of a 4" drop tube assembly.  When the fuel oil level increases to approximately 95% of tank capacity (Level “A”), the main valve closes.  A small bypass valve remains open to permit delivery hose draining at a rate of approximately 2-5 GPM.  If the oil level reaches Level “B” (5 inches above Level “A”), the bypass valve closes to prevent accidental or intentional overfilling.
 
Caution: Model 71 Overfill Prevention Valve is for use with “gravity fill” systems only, and is not intended for “pumped-in fill” applications.  It is for diesel or No. 2 fuel oil only.