Everything you need to know about the professional pressure washer

A pressure washer is a machine that uses a high-pressure water jet to remove dirt and scale from any solid surface.
The water coming from a water source (around 2 bar pressure) is set under pressure (up to 700 bar) by means of a piston pump powered by an electric or endothermic  motor and flows out through a nozzle mounted on a lance, thus succeeding in breaking up and removing dirt on the surface to be treated.

The four basic variables that characterize and distinguish pressure washers from each other are:

• Pressure
  The force with which water flows out of the nozzle of the lance, that is, the force water exerts on the surface to be washed. It is commonly measured in bars.
  > Learn more: Nozzles and heads: the most important parts in the pressure washers
• Flow rate
  The amount of water the pressure washer is able to pump in a given unit of time. It is commonly measured in l/h.
• Temperature
  Depending on whether the water, after being brought under pressure by the pump, is heated or not by a boiler, a distinction is made between cold water pressure washers and hot water and/or steam pressure washers. 
   
• Power and type of motor
  The power of the motor defines the "size" of the pressure washer and identifies its relevant fields of application; it is expressed in HP (Horse Power) or kW.
  For professional use, greater power ratings than 3 .0 kW and a three-phase power grid are needed, or one must opt for a pressure washer with an endothermic (petrol) engine.

These variables are interconnected; consequently, when selecting a pressure washer, the ratio between flow rate and pressure must be carefully evaluated so that the best solution for your needs and applications can be found.
Similarly, the power of the motor is related to the pump it has to drive: the more the pump has high values of flow rate and pressure, the more power will be required for the motor connected to it.

Learn more about how the professional pressure washer works

Th high pressure washers can be distinguished mainly in two categories in relation to the temperature of the water used:

• Cold water high pressure washers
  They only use the water pressure supplied by the piston pump.
  They can be used with chemical cleaners and can perform most cleaning operations including the removal of dirt and incrustations.
  The situations in which we can successfully use a cold water high pressure washer are many and range from hobby and domestic uses to more industrial and professional uses.
• Hot water/steam high pressure washers
  They are equipped with a boiler which, through a coil, heats the water coming out of the piston pump. They are used to remove grease and oil originating from hydrocarbons or compounds of vegetable and animal origin, as the high temperature facilitates the dissolution of oily dirt.
  Hot water high pressure washers are used in various sectors, such as the technical agriculture, food industry and general industry and are an excellent solution for the cleaning of machinery, machine tools, engines and transport equipment. They are also an excellent means for sanitizing things and environments.

All high pressure washers, whether cold or hot water, are able to achieve the same type of result, i.e. the cleaning of a surface.
But then, which one to choose: a hot water washer or a cold water washer?
Basically what distinguishes them is how the result is achieved:

• Heat increases the molecular velocity of the cleaning agents that penetrate dirt particles more easily
• Molecular agitation performs the same function as heat, but exploiting the pressure of the water hitting the surfaces
• The detergent breaks the chemical bonds that have been created between dirt and surfaces and, through reagents, emulsifies oil and grease, allowing them to bond with water

It is therefore clear that, the results being equal, a hot water machine will need less detergent and/or pressure as the heat will be important in activating the molecular bond between the particles.
In addition, if we use cold water to remove a spot of grease the result will be mainly to create many hydrogenated micro-particles that, like a wax, will scatter over the entire surface. Cold water washers, however, have other advantages linked to lower costs and reduced energy consumption.

Let us therefore try to summarise the advantages and drawbacks of cold water and hot water washers:

The choice between electric and endothermic version for professional use is closely related to the type of power supply available.
The petrol-powered pressure washers are the ideal solution when there is no electrical connection in the work area or where the latter does not achieve the appropriate power, in any activity where a fully independent  and easily transportable pressure washer is needed.
Electric pressure washers, on the other hand, besides being quieter, can also be used inside sheds, such as food industries, indoor car washes, etc. In terms of performance, there are state-of-the-art electric models that boast performance very similar to endothermic ones.

> Learn more about the differences between electric and endothermic professional pressure washers

The uses that can be made of a pressure washer in the professional field are countless. In fact, pressurized water is capable of removing all kinds of dirt, thus simplifying your work and making cleaning easy and inexpensive. But the choice of a pressure washer, as with any machinery, is inevitably linked to the purpose for which it is used and the professional field in which it has to operate.

Let’s look at some examples.

• The professional pressure washer in agriculture

Professional pressure washers used in agriculture are mainly hot water ones which can remove greasy dirt, such as mud or manure, especially to ensure compliance with hygienic requirements imposed by laws in spaces such as stables or warehouses.

Models with high power, pressure and water flow rate are to be preferred, so as to wash in less time and using less water, pressure and detergent, which also saves the environment.

• The professional pressure washer for mechanical shops

Metalworking companies and shops can be considered one of the industries where the most dirt is produced, including metal shavings, dust, oils and emulsions. In addition to ensuring efficient production, cleanliness in these cases is especially important for worker safety and proper maintenance of machinery and tools.

In the metalworking industry, even more so than in agriculture, the most suitable professional pressure washers are hot water ones. Cold water, in fact, is ineffective against grease because it only succeeds in dispersing the hydrogenated microparticles making up oil and grease, but fails to remove them quickly and thoroughly from surfaces.

• The professional pressure washer in the food industry

Food production is the sector that requires hygiene and cleanliness more than any other, both to ensure product quality and to meet specific regulations.

From the small laboratory to the large factory, places such as dairies, slaughterhouses or butcheries cannot do without the use of a professional pressure washer to remove solid processing residues from surfaces and equipment, or to perfectly clean tanks, floors and laboratories where contaminable materials such as meat, milk, wine, fruits, vegetables, flour and grains are processed.

Thus, one can choose between cold water pressure washers and pressure washers capable of producing hot water. To fight against the formation of bacteria, germs and other organic impurities, hot water is more suitable, but these models, when used indoors, require a special fume conveyor.

• The professional pressure washer for cleaning construction sites   

In this video learn about our FDX professional pressure washers: blades, XL and Endurance at work in a construction site and the amazing performance of the 700 BAR series

Want to get the most out of your pressure washer? Here are some useful tips and a few small tricks:

1. For cleaning vertical surfaces, wash from the bottom up and rinse from the top down.
2. Regularly check the cleanliness of the inlet water filter and of the nozzle on the lance
3. Using too much cleaner makes the rinsing step more difficult and pollutes the environment more. Best not to overdo.
4. Keep the nozzle at an angle with respect to the washing surface and at a sufficient distance to avoid damaging it.
5. Always avoid spraying water on lighting or air conditioning systems, electrical outlets or vents.
6. Keep the jet moving to prevent water from ruining surfaces.

• Total Stop
  This is a special function that automatically stops the pressure washer with electric motor when the spray gun is closed (no water flow in pump delivery), bringing it to stand-by. When the spray gun is reopened, the pressure washer restarts since the machine is still energized.
  The Total Stop device can be instantaneous type (TSI), if the motor turns off at the same time as the spray gun closes, or delayed type (TSR), if the motor turns off  about 15 seconds after the spray gun closes.
  To avoid leaving the machine energized for too long, some models have a safety device (general stop) that permanently shuts the machine down after 15 minutes. 
  IMPORTANT: during Total Stop the pressure washer is for all intents and purposes operational.
  Should you stray during use, it is always necessary to turn the pressure washer off from the power switch, relieve residual pressure by pulling the spray gun lever and disconnect the electrical cord from the power outlet. In the case of spontaneous restart from the Total Stop condition, the problem may be caused by leakage in the delivery circuit, so its soundness should be checked.
• Easy start 
  A device that reduces the starting torque of the motor pump by assisting the start of the electric motor in precarious connection conditions, such as when there is a drop in electrical voltage.
• Self priming
  Some models of Comet pressure washers can work in self-priming mode and be powered by an external source (e.g., tank).
• Thermostatic valve
  Some models of Comet pressure washers are equipped with a thermostatic valve. This device prevents overheating of pump seals during prolonged by-pass operation.

Thanks to the professionalism and know-how gained in more than 60 years of business, Comet is able to offer great advantages and opportunities to its dealers.
Our goal is to enable you to provide your customers with an innovative, quality product with a huge demand in the market.
You will always have an experienced and qualified team on hand to meet your needs and those of your customers.