Pump pressure rating vs. pressure washer pressure rating

For power washers, the overall psi rating can exceed the pump's capacity through the design of the nozzle, gun, and high-pressure hose. A smaller nozzle orifice increases the velocity and pressure of the water jet, while a durable, narrow-diameter hose ensures minimal pressure loss during transmission. Together, these components optimize the system to deliver higher pressure at the point of use. 

The power washer's max rating is measured using the nozzle with the smallest orifice, which produces the power washer's max psi rating. 

Note: pressure per square inch (psi) - is the unit measure that quantifies the force with which water is propelled from the power washer to the surface. 

Example:

Generac's 3100psi power washer is designed with a 2400psi pump on it. The psi rating is increased from the pump's 2400psi rating to 3100psi with the hose, gun, and nozzles.