People often think that any nozzle will be OK in my pressure washer.  So, they grab a nozzle from some other unit nearby and then find that the pressure washer doesn’t have as much pressure as before or gets too much pressure and cycles the pressure up and down.

Most people don’t realize how important the pressure nozzle in.  The truth is that all components in a pressure washer (pump, unloader, hose, gun, and wand) are engineered to withstand the pressure.  The nozzle on the end creates the pressure.

There are generally four degree spray patterns for nozzles…0°, 15°, 25° and 40°, but there a many different hole sizes…from a #2 (0.034) to a # 40 (0.156).  See the attached Nozzle Chart.

If you have a washer rated for 4 gpm @ 4000 psi, you can see on the Nozzle Chart that the correct nozzle is a #4.  If you use a # 6.5 nozzle you will get 1500 psi and if you use a #3 nozzle you will get almost 7000 psi.

Most legitimate pressure washer manufacturers will have a model # and serial # stamp on the unit that will include the correct nozzle size.  If you’re unsure of the specifications on your machine, you should take it to CETA Certified (Cleaning Equipment Trade Association) pressure washer distributer in your area.  Based on the information they can get on the motor and the pump, they should be able to give you the correct gpm, psi, and nozzle size for correct, safe operation.