What should I do before plugging in the pressure washer for the first time?

Make sure the motor switch is pushed to the OFF (0) position before plugging the unit into the power outlet. You should also check that the electrical supply voltage and frequency (Volt/Hz) correspond to those specified on the pressure washer rating plate. Additionally, the GFCI may need to be reset when first plugged into the electric outlet by pressing the Reset button until the power light indicator illuminates.