The Wolverine/Prince valve Model WR-1900 has a built in adjustable pressure relief. For this model, the excess flow port must be connected to the tank. It should be noted that whenever this or any valve is used to bypass or restrict flow, heat will be generated. Steps may be required to keep oil temperature from becoming too high.
Relief Pressure information:
Inlet relief protection available on "WR" models. Relief pressure preset at 1500 PSI. To adjust, remove acorn nut, turn adjusting screw clockwise to increase pressure, counterclockwise to reduce pressure. Reinstall acorn nut after adjusting. Use a pressure gauge when making adjustments.