GENERAL GUIDELINE ON SPRAY NOZZLE SELECTION
Pressure Washer Spray Nozzle can be identified by the nozzle "number", a four or five digit number that is stamped on the nozzle, which indicates the spray angle and orifice size. In all cases the first two digits of the nozzle number indicate the spray angle (disperse) in degrees.
EXAMPLE: 00 is 0 degree, 15 is 15 degree, 25 is 25 degree and 40 is 40 degree. The last two digits of the nozzle number indicate the orifice size, a standard industry designation. EXAMPLE: 06 is a 6.0 orifice, 55 is a 5.5 orifice. These numbers correspond to the actual dimensions, giving the size of the orifice.
They do not however directly indicate gallons per minute, flow rates or inches in diameter of the orifice. Some power washers come with an adjustable nozzle (called Vari Nozzle) that is attached to the end of the wand. The fan spray may be adjusted by turning the nozzle, chemical may also be applied by pulling out word on the nozzle.