To operate correctly, pressure washers need the correct nozzle size. To get the right one, you need to determine the orifice size. This is the diameter of the hole in the spray nozzle. How do you find it?
Simply find the PSI Rating of your pressure washer along the top of the chart. Then find the Gallons Per Minute (GPM) along the left side. Where they meet is your pressure washer's orifice size.
For example: If your pressure washer is rated 3500 PSI and 3.5 GPM, then according to the nozzle chart you would need to buy nozzles that had a 4.5 orifice. If your pressure washer was 4000 PSI and 4 GPM, you would need to buy nozzles that had a 4.0 orifice.
Why does the correct size matter? Well, let's say you select a nozzle size that is too small for your particular pressure washer it will damage the pump. And if you chose a nozzle too big for your pressure washer it will let too much water through and your machine will not clean up to the psi that its rated.
