Abstract: The control system is utilized in a high pressure liquid spraying system including an internal combustion engine, a pump driven by the engine, a source of liquid connected to the pump and a spray nozzle assembly connected by a high pressure conduit to the output of the pump. The control system includes an enclosure and a valve assembly mounted near the pump. The valve assembly is operated by an electric switch mounted on the nozzle assembly and connected to a first solenoid valve in a hydraulic system for operating the valve assembly. The valve assembly includes a hydraulic cylinder which is mounted on the enclosure and which has a plunger positioned to open a ball valve of the valve assembly which is mounted within the enclosure and which is connected to the output of the pump.