Webster RV series valves are designed to provide fuel oil pressure regulation in oil heating applications such as transfer or supply pump systems or high firing capacity burners. The RV series are designed to provide system pressure regulation for #1 through #6 fuel oil grades Rated pressure ranges are for 0 to 500 psi. RV-2000 models also provide delivery cut-off for capacities to 150 gph. RV-2100 regulates pressure only for capacities to 150 gph. RV-3000 regulates pressure for up to 600 gph. It can also be used as a relief valve.