The best way to get the most out of your pressure washer is to leave the unloader valve completely open and control the pressure output using a different sized nozzle. The Kranzle K1122TST is rated at 2.1 Gallons Per Minute(GPM) Output. This 4.0 sized nozzle at 2.1 GPM gives us 1100PSI output.
This nozzle emits a 40 degree spray pattern. This pattern is good for washing.
Use the Nozzle Calculator to help you choose the correct orifice size HERE