Axial cam

Portable Pressure Washer Familiarization and Troubleshooting Guide Section 1 • Operation

3. The linear movement of the pistons pump a fixed volume of water through the pressure washer system. The volume of water flow depends on a. piston diameter b. length of piston stroke c. number of pistons d. number of piston strokes per minute. 4. The pressure that builds up in the system then depends on the size of the spray nozzle orifice (item 1). 5. The fixed volume of water flows past an unloader/pressure regulator valve (item 7), an optional chemical injection assembly (item 8), through a highpressure hose (item 10), and to a spray gun (item 4). 6. The spray gun permits the operator to turn the flow of water on or off. 7. If the water flow is turned off, water pressure within the pump will increase until the unloader/regulator valve (item 7) is moved off its seat. Flow is then bypassed back to the pump inlet through an internal bypass channel.

Fluid bypass continues as long as the spray is turned off. 8. Recirculating bypass water can become hot enough to damage seals and other pump parts. Some pressure washer systems may be equipped with an internal thermal relief valve which automatically replaces hot water with cool water. 9. The optional chemical injection assembly (item 8) permits detergents or other chemicals to be drawn into the water stream and (along with the water) discharged from the nozzle. 10. The nozzle collar (item 2), a part of the spray gun nozzle, permits easy selection of high or low velocity spray or a fan or stream spray pattern. 11. An optional easy start valve relieves pump outlet pressure during cranking for quicker and easier starts. 12. As a nozzle is used, it often becomes clogged with various types of matter. A clogged nozzle obstructs the water flow causing a reduction in outlet pressure. It also may cause the water stream to pulsate while the gun is triggered. Therefore, the nozzle should be checked and cleaned before every use, using the cleaning kit provided with every Generac Portable Products® pressure washer system. 13. The flow of water through the nozzle will gradually wear away the nozzle orifice, causing the orifice to become larger. This enlargement will eventually cause a reduction in system pressure. For this reason, the nozzle should be replaced periodically and always replaced with the correct nozzle.