a nozzle assembly comprises a hollow nozzle body having a central bore and a plurality of ports extending through the body from the central bore ; and a switching valve cartridge disposed in the central bore that directs fluid flow to ports upon application of fluid flow above a predetermined threshold to the inlet and direct fluid flow to different ports upon fluid flow having subsequently dropped below the predetermined threshold and then exceeding the predetermined threshold . the cartridge comprises a cylindrical cartridge case having a front portion and a cup shaped rear portion , a cylindrical poppet slidably disposed within the cup shaped rear portion of the cartridge case , and a biasing member within the cartridge case between the front portion of the case and the poppet urging the poppet away from the front portion of the cartridge case .