Using a Downstream Injector with a Pressure Washer
Optimizing Downstream Injecting for Pressure Washers Downstream injecting is an effective method for mixing chemicals after the pump in pressure washers, preventing caustics from damaging the pump head. The injector draws chemicals into the hose under low pressure, spraying the mix through a low-pressure nozzle. Key Considerations: Gravity: Spraying at heights over 15-20 feet can increase back pressure, causing the injector to stop working. Hose Length: Effective up to 200 feet; longer hoses may reduce chemical draw. Injector Size: Must match the pressure washer's GPM. Size 1.8 for 2-3 GPM, 2.1 for 3-5 GPM, and 2.3 for 6-8 GPM machines. Nozzle Size: 3-5 GPM machines need a 30-40 orifice size; 8 GPM machines need 50-60. Smaller sizes create too much pressure for the Venturi effect. Properly considering these factors ensures efficient chemical mixing and optimal cleaning performance. Link to expanded article