The 1” and 1 1/4” Model 80DI VFD patented submersible pump check valves from Flomatic for use with variable-frequency drive control submersible pumps are designed to minimize flow losses and hydraulic shocks in the pumping system. Standard check valves will “chatter” and be noisy when a VFD goes to low flow, causing premature wear and eventual failure. This unique valve features a standard epoxy-coated, (NSF®-approved powder) ductile iron body to support deep set pumps. The radiuses of the valve seat allow a self-cleaning “one point swiping action” by the radius-edged, custom-molded rubber seal disc. Corrosion-resistant internal parts.