Proper nozzle size is imperative to proper washer operation. The orifice (hole) size in a nozzle is designed to pass a certain volume of water at a certain pressure. If the nozzle is too large then the pressure will drop. If the nozzle is too small the pump will be forced to recirculate some of the water volume which creates heat and wastes horsepower. It can also allow the pressure to increase above the pump’s design pressure which may damage it. Nozzles wear after time and should be inspected if pressure begins to drop. Often pressure drop due to nozzle wear is misdiagnosed and the setting of pressure relief valves or unloader valves is increased. This does not improve this condition but rather causes excess pressure to build up when the trigger gun is released. This condition can damage your pump.

Spray angle also affects performance. The narrower the spray angle the more impact force that is applied to the surface at a given distance from that surface.

A 40° or 60° nozzle provides the widest coverage but the lowest impact force.

A 15° or 25° nozzle provides better impact force with good coverage.

A 0° nozzle provides a straight stream with maximum impact force and the least coverage. The coverage of this type of nozzle can be improved with the use of a rotating or “turbo” nozzle with very little loss to impact force.

Care must be exercised when using any nozzle and especially straight stream or “turbo” nozzles because they can easily damage surfaces and present a serious risk of injury if they are directed at any part of the body.