Opening Pressure Test

Open tester shut off valve to pressure gauge 1/4 turn. Slowly depress tester lever and observe pressure gauge. Note pressure at which needle stops, indicating pressure increase (nozzle does not chatter) or at which pressure drops substantially (nozzle chatters).
Maximum pressure is opening pressure. Lowest acceptable pressure is 1500 psi (105 kg/cm² ). Replace any nozzle which does not meet lowest acceptable pressure. Release tester pressure.