How does a pressure washer work

Main operation of the pressure washer: the pump

The core function of the pressure washer (with either cold water or hot water) is to spray high pressured water through a lance, in order to achieve effective cleaning, with or without detergents.

Some pressure washers also include a heating functionality to spray hot water

The pump is powered by a motor: either an eletric engine or a gas one. The stronger the engine is, the higher the output pressure could be. Thus, the water jet might sometimes reach 500 bars. The water flow is about 500 liters per hour (L/h). In comparison, garden hoses are about 3 500 L/h. Hence, a pressure washer saves water.

Composed of a pump, the operation of a pressure washer applies the same principle whatever the model is:

• the water brought to the tool is compressed by the pump
• the water is then released in the direction of the lance upon pressing the button on the latter.

The water supply is essential, because any rupture will cause a cavitation effect (appearance of air bubbles) which can damage the operation of the pump of the pressure washer. This is also the reason why a slight delay is often noticeable after starting the pressure washer: the device ensures its water supply before starting the compression operation.

In addition, in order to avoid any damage, the pressure washers are equipped with valves in series, allowing both to retain the pressure in the compression chamber and to avoid the phenomenon of cavitation.

Detergent: how does it work with a pressure washer?

Most of the pressure washers available on market are equipped with a detergent tank which allows for instance to clean pavers, windows or concrete.

The detergent is naturally aspirated by the high-speed water flow, thanks to a phenomenon called the “venturi effect”. The operation of a pressure washer with additive tank takes advantage of this principle in order to add the detergent to the water, without damaging the pump. It is therefore possible to use a wide variety of detergents without any risk for your equipment.