How Pressure Washers Work

Ever wondered how your pressure washer transforms water into a dirt-destroying weapon? In this article, we’ll provide a step-by-step breakdown of how pressure washers work, demystifying the process that turns water into a high-pressure cleaning dynamo. Whether you’re a seasoned user or new to the world of power cleaning, join us on a quick tour through the key components that make pressure washers the go-to solution for a pristine clean.

1. Water Supply:

• The pressure washer is connected to a water source, typically a garden hose at home or a more professional-looking alternative in commercial or industrial settings.
• This is where the water begins its journey into your pressure washer.

2. Pump System:

• The pressure washer has a pump that pressurises the water.
• This pump is typically powered by either an electric motor (see: Ehrle Range) or an engine (see: NPC range), depending on the type of pressure washer.

3. Pressure Buildup:

• The pump speeds up the rate at which water is pulled into your machine and forced out the other end of the pump and into the hose running to your trigger gun.
• This increased speed translates to increased force, eventually creating pressure.
• Note: It’s crucial to have a pressure washer that doesn’t outstrip your water supply, either by ensuring a good water flow rate or using a breaker tank.

4. Hose and Nozzle Attachment:

• At the end of the hose, there is typically a gun and lance. 
• The lance has a nozzle at the end.
• The nozzle has a small hole in it, creating a bottleneck for the water to pass through.
• The increased rate (or force) of the water-flow from the pump pushes it through the hose toward and through the nozzle.

5. High-Pressure Spray:

• Assuming you have your trigger pulled, water is allowed to continue its rapid journey toward the nozzle.
• Forced through the small hole in the nozzle, the water is pressurised as it tries to escape through the hole.
• Water exits the nozzle as a pressurised spray or jet of water.

6. Cleaning Action:

• The water, pressurised by the pump leaves the nozzle as a jet of water.
• The pressure increases the speed of the water exponentially, increasing the force at which the water hits dirt and grime.
• Assuming the pressure is great enough, the jet of water will break up and remove the dirt and grime.

7. Adjustable Pressure/Water Flow (Optional):

• Many pressure washers have adjustable pressure settings.
• These typically reduce the power output of the pump, reducing the amount of water that is pulled through the pressure washer (see 2).
• The reduced water flow reduces the force at which the water is pushed through the nozzle.
• The reduced force lowers the pressure.

8. Detergent Injection (Optional):

• Some pressure washers have a detergent tank or an attachment for adding cleaning solutions.
  • Many of these attachments have larger nozzles, reducing the pressure (see: chemical foamer) at low pressures.
  • The Ehrle range, such as the KD premium range, inject chemicals into the water flow. These mean chemicals can be applied under pressure, keeping up that dirt blasting capability!
• Chemicals are useful for breaking down dirt, grime and particularly traffic film.

9. Steam Cleaning (Optional)

• Some pressure washers also include a burner for heating water.
• The Ehrle HD and HSC range, for instance, can heat water to 150°C.
• Heat can help break down dirt and grime.

10. Automatic Shut-Off (Optional):

• Certain pressure washers are equipped with automatic shut-off features that stop the motor or engine when the trigger is released. 
• This helps conserve energy and prolong the life of the machine.

In a Nutshell: Decoding Pressure Washer Power

From water inlet to high-pressure spray, we’ve unravelled the secrets behind the cleaning prowess of pressure washers. Whether you’re a seasoned user or a newbie in the realm of power cleaning, understanding this process reveals the precision in every drop. The adjustable pressure, optional detergent boost, and automatic shut-off features add versatility to its might.

Ready to elevate your cleaning game? Explore our range of advanced pressure washers, designed to unleash precision and efficiency in every spray. Whether you’re in the industrial, commercial, or residential sector, discover the perfect cleaning companion tailored to your needs. Visit our product page now to browse our cutting-edge models and take the first step toward a spotless, pristine clean. Or, if you would like advice, give us a ring at 01652 659 759 or send us an email via our contact form or a message via messenger (see facebook messenger icon in bottom right).

What are the different types of pressure washers?

Pressure washers are powerful tools that can be used to clean various surfaces. There are several types of pressure washers, powered in different ways, mounted in different ways and capable of doing different things. Below are many different ways we can categorise pressure washers, but bear in mind that many pressure washers will fall into multiple categories. For example, an electric, engine or hybrid pressure washer may also be mobile or static, and hot or cold water. Moreover, some of these pressure washers are more suited to commercial, industrial or domestic tasks.

For our article on what is a pressure washer? Click here.

Article Contents

1. Electric Pressure Washers
2. Engine-powered Pressure Washers
3. Hybrid Steam Cleaners
4. Hot Water Pressure Washers (or Steam Cleaners)
5. Cold Water Pressure Washers
6. Mobile Pressure Washers
7. Static Pressure Washers
8. Trailer Pressure Washers

1. Electric Pressure Washers

Electric pressure washers are powered by motors that run on an electrical supply. They are typically quieter and more lightweight than engine-powered models, making them easier to move and store. Depending on the power supply (240-volt vs 400-volt supplies), the power outputs of electrical pressure washers can be vast. 

240 vs 400 volts

On 240-volt supplies, the power output is typically a payoff between water flow and pressure due to the bandwidth of the electrical supply. However, 3-phase (400V) pressure washers can boast large flow rates of 20+LPM and operating pressures of 220+ BAR. 

The advantage of 240-volt pressure washers is that these use standard, mains UK supplies. 3-phase/400-volt pressure washers require a special supply that is not always available. (If you are unsure, try to find out what supplies you have available via your electrician. Alternatively, we can and often will double-check.)

To put the power difference into perspective let’s compare two Ehrle cold water pressure washers, the KD623 and the KD1140. The KD623 is a 240V pressure washer and boasts 160 BAR of pressure and a discharge capacity of 10 litres per minute. The KD1140, on the other hand, boasts 250BAR and 15 LPM. 

The KD1140 is not the most powerful cold water pressure washer that Ehrle manufactures. Yet, it is vastly more powerful than the KD623, which is restricted by its 240V supply. The KD1140, for instance, supports 90BAR and 5LPM (400 litres per hour) more than the KD623.

2. Engine-powered Pressure Washers

Engine-powered pressure washers are ideal for all sorts of cleaning tasks, from lighter domestic jobs right through to professional industrial or commercial work. Like electrical pressure washers, they can have substantial flow rates and pressure outputs. Engine-powered pressure washers are typically heavier than electric models, but they offer more versatility and power as they do not require an electric supply.

Naturally, as you may expect, the size of the engine tends to correlate with the pressure and water flow outputs. Like with the electrical pressure washers, there is only so much power an engine can produce. However, just like with the electrical pressure washers how this power is allocated (to pressure vs water flow) can vary.

If we take a look at the Nailsea Power Cleaning Honda Driven Range, for instance, we can see that despite the same engine, they can be set up to emphasise water flow over pressure (or vice versa). The Eco HR 20-21 and 25-15 both use the Honda GX 390. However, one has a pressure of 200BAR at 21LPM (20-21) and the other has a pressure of 250BAR at 15LPM (25-15). Essentially, the engine has a fixed output, based on its power but, the power can be used to create more pressure, more water flow or a balance between the two.

3. Hybrid Steam Cleaners

Due to the electrical demands required to generate both heat (especially at steaming temperatures!) and pressure, it is common for steam cleaners to run on both electricity and fuel. The electric supply typically powers the motor, which in turn powers the pump, while the engine powers the burner for heating water. The cabling and supply required for all electric steam cleaners are pretty hefty. Therefore, sharing the burden can be desirable. Particularly for mobile units.

The Ehrle HD and HSC ranges, for instance, are our primary range of hot water pressure washers. (The difference being the HD is a mobile pressure washer, while the HSC is static.) Both these types of steam cleaners can produce water (or should that be steam?) at temperatures of 150°C. To do this, the hybrid versions use an electric motor to power the pump and a diesel-powered burner to heat the water.

4. Hot Water Pressure Washers (or Steam Cleaners)

Hot water pressure washers are designed to clean surfaces with hot water instead of cold water. They are ideal for removing grease, oil, and other tough stains from surfaces. They can also be used to sterilise surfaces (so long as they can reach sterilising temperatures!)

The Ehrle HD and HSC ranges are our primary forms of steam cleaners. Each of these is capable of cold water cleaning and hot water cleaning from 30-99°C. By reducing the water flow and pressure slightly, however, they can also clean at sterilising temperatures of 150°C.

We also sell the Ehrle HDD, which is an entirely engine-driven hot water pressure washer capable of cold water and heated water cleaning from 30-98°C. It does not have the capacity for steam cleaning at 150°C.

It is also worth bearing in mind that Ehrle’s KS range (823 & 1140) boasts parts that allow it to take pre-heated water of up to 80°C. In other words, so long as you can keep up the water flow, you can put hot water into your KS pressure washer, giving you warm to hot water cleaning potential.

5. Cold Water Pressure Washers (or Jet Washers)

Cold water pressure washers are the most common type of pressure washer and are suitable for most cleaning tasks. They are typically less expensive than hot water models and are ideal for cleaning surfaces such as decks, patios, and sidewalks. 

Cold water pressure washers also tend to be smaller and lighter than hot water pressure washers as they do not require heating components, such as a burner. For example, the KD940 is 79cm long and less than 60cm wide. It also only weighs 58kg with a hose reel. The hot water equivalent, the HD940, on the other hand, is over 100kg heavier (189kg, with a hose reel), 30cm long and 10cm wider. 

Cold water pressure washers can be incredibly compact. Take the Kranzle 1050 series, particularly the 1050p, or the Kranzle HD 7/122. Both of these pressure washers boast a robust brass pump, which does make them heavier than cheaper domestic pressure washers. The 1050p, for instance, weighs 19kg, while the HD 7/122 weighs 22kg. Both are designed to be carried, with the 1050p only being 39cm long, 29cm wide and 37cm tall. Dinky.

6. Mobile Pressure Washers

Mobile pressure washers are designed to be as portable and manoeuvrable as possible. They are ideal for cleaning outdoor surfaces or for use in remote locations.

The portability of mobile washers varies depending on the application. As we explored in previous sections, engine and hot water pressure washers tend to be heavier and bigger. Therefore, the portability of pressure washers such as the HD1240 or the Yanmar driven 20-15 is less than the compact Kranzle 1050p (p standing for portable), which can be carried.

That said, the HD1240 and the Yanmar driven 20-15 are very mobile. Both are mounted on good quality wheels (as opposed to castors), and both have a strong frame and handle for pushing or pulling them about.

7. Static Pressure Washers

Static pressure washers (or steam cleaners) are designed to be a fixed unit, often a floor-standing cabinet (see HSC range) or a wall-mounted washer (see KS 823 or 1140). They are ideal for cleaning fixed locations or objects and materials that are themselves mobile, such as cars, lorries, and agricultural and plant machinery.

Fixed in one location, static pressure washers are perfect for those who want a cleaning hub: a dedicated location for their high-pressure cleaning equipment. The beauty of the HSC or KS 823 /1140 is that they can be set up to store your equipment in one place. 

The other great thing about statics is that they can be accessorised and customised to suit what you need. The HSC range, for example, are essentially big cabinets. Inside there is a shelf that compartmentalises them. The upper part contains the pressure washer while the lower half is left clear for storing diesel (1x60L tub) and chemicals (2x25L tubs). However, depending on the need for chemicals this space can also be utilised for storing anything. Guns, lances or a hose reel. Most commonly, though, we have tended to fit these things to the sides or nearby to the pressure washer, leaving the chemical space for chemicals. But the choice is there for you!

8. Trailer Pressure Washers

Trailer bowser pressure washers are portable units that are mounted on a trailer and equipped with a water tank for extended cleaning operations. They are designed to be towed by a vehicle, making them ideal for use on construction sites, farms, and other remote locations where access to a water source may be limited.

One of the major benefits of trailer bowser pressure washers is their portability. They can be easily moved from one location to another, allowing you to take your cleaning operations wherever they are needed. Additionally, the water tank on the trailer allows for extended cleaning operations without the need for a nearby water source.

Our Yanmar Driven Trailer Bowser (also available with a petrol-driven Honda engine) features an 1100-litre tank, gearbox-driven interpump, 40m hose reel and gun and lance.

Close

Pressure washers can be a highly effective tool for cleaning a variety of surfaces, from outdoor patios and driveways to industrial machinery and vehicles. Choosing the right pressure washer can not only improve the efficiency of your cleaning process but also save you time and money in the long run.

Whether you’re looking for an electric, engine or hybrid-powered pressure washer, or hot water, cold water, mobile, static or trailer bowser model, there is a pressure washer out there to fit your specific cleaning requirements. So, take the time to research and evaluate your options to find the pressure washer that will provide you with the best results and value for your money. As part of that research, why not get in touch with us? We have over 25 years of experience advising and installing high-pressure cleaning solutions. Here’s our number 01652 659759. Or, feel free to use the messenger icon on the bottom right of your browser, or our contact form.

A pressure washer (also referred to as a jet washer or steam cleaner, if it is a high-temperature hot washer) is a form of cleaning equipment that uses a high-pressure stream of water to remove dirt, grime, and other stubborn stains from surfaces. 

The high-pressure stream of water is created by a motor or engine that powers a pump. This pump effectively speeds up the water flow through the pressure washer, which is then pushed through the nozzle at the end of a trigger gun and lance. Similar to how you might try to create pressure with your garden hosepipe by squeezing it, the nozzle creates a smaller gap for the water to pass through. The elevated force at which this happens in a pressure washer, however, enables them to create a high-pressure stream of water that can blast away dirt and grime from surfaces such as concrete driveways, patios, vehicles and outdoor furniture.

Pressure washers come in various sizes, from small handheld units for light, often domestic, cleaning tasks to large industrial units for heavy-duty cleaning. They can be powered by electricity, petrol, diesel or other fuels, and the pressure of the water stream can range from 70 to 300+ BAR at a flow rate of 5 – 25+ litres per minute. 

Here at Idro Power, we deal primarily in industrial and commercial cleaners that predominantly operate between 140 – 250 BAR and flow rates of 7 – 20 litres per minute. However, for specialised cleaning, we often build or upgrade rigs that are capable of supporting multiple guns or higher flow rates, such as 30LPM and higher pressures (250+ BAR).

Pressure washers are commonly used for cleaning surfaces and materials in a range of domestic, commercial and industrial settings. For example, they can be used for cleaning vehicles, boats, and other machinery. Or, pressure washers of a higher pressure output can even be used for removing paint or graffiti from surfaces, as well as for preparing surfaces for painting or staining.

TLDR

Pressure (or Jet) washers are powerful cleaning tools that can be used for various tasks. Whether cleaning your driveway, preparing a surface for painting, or removing stubborn stains, a pressure washer can make the job easier and more efficient.

Pressure vs flow rate: what do these tell us about pressure washers

When considering a pressure washer for high-pressure cleaning, it’s essential to delve into the specifications that truly define its cleaning performance. Two critical factors to keep in mind are pressure and flow rate. This article aims to clarify the meanings of pressure and flow rate, emphasising their significance in the realm of high-pressure cleaning.

Pressure: The Driving Force

Pressure, in the context of a pressure washer, represents the force exerted on dirt, grime, and mud. Simply put, the higher the pressure, the more powerful the cleaning capability of the pressure washer. However, there’s more to pressure than sheer force.

Understanding Pressure (in theory):

Pressure is fundamentally a measure of force over an area, expressed by the equation P = F / A. While specifications often use BAR, visualising pressure in Pounds per Square Inch (PSI) makes it more tangible. For instance, if a 1lb weight is laid atop of a 1-inch cube, the pressure on the cube is 1 PSI.

Increasing pressure involves either enhancing the force or reducing the area. This practical insight helps us grasp the theoretical foundation behind pressure washers.

Pressure in the Practical World of Pressure Washers:

Pressure washers embody the mathematical principles of pressure. The force a pressure washer generates depends on the pump and motor. A more potent pump and motor allow for increased force by pulling more water through. The nozzle at the lance’s end determines the area across which the force is applied. Larger nozzles reduce pressure by spreading force over a larger area.

Maximum Pressure:

Similar to overclocking a computer, using a smaller nozzle can exceed the recommended operating pressure. This tactic reduces the area, increasing pressure. Caution is necessary to avoid safety concerns and potential damage to the pressure washer.

Why Pressure Matters:

Pressure is a critical indicator of a pressure washer’s ability to break up dirt. Higher pressure means greater force, surpassing the dirt’s resistance. Exceeding this resistance accelerates dirt removal, making higher pressure crucial for effective cleaning.

Flow Rate: The Volume of Water Dispensed

The flow rate of a pressure washer refers to the amount of water it dispenses over time. In the case of our product specifications this is typically expressed in Litres per hour or Litres per Minute. Water flow is integral to cleaning efficiency and is closely tied to pressure.

Interconnection of Flow Rate and Pressure:

Pressure washers pull water at an accelerated rate to generate force. The flow rate and pressure are interlinked, with controls that reduce pressure also reducing flow rate. This relationship allows for variable pressure on some machines, adjusting both pressure and flow rate simultaneously.

Why Flow Rate Matters:

Flow rates are crucial for multiple reasons, including the water inlet supply. Larger machines may require breaker tanks due to their higher water consumption. In terms of cleaning performance, higher flow rates lead to wider and more efficient cleaning spans, reducing the need for multiple passes.

Link Between Flow Rate and Pressure:

Reducing the nozzle size or lowering the flow rate both result in increased pressure. This link is exemplified in pressure washers like the Ehrle HSC range, which offers variable flow rate/discharge capacity.

Conclusion:

Understanding the dynamic relationship between pressure and flow rate is paramount for making informed decisions when selecting a pressure washer. These specifications not only define cleaning performance but also influence the machine’s versatility and efficiency in various cleaning scenarios.

In this article, we will discuss some of the specification terminologies on our site. Notably, those specifications that relate to machines that use liquid fuel such as:

1. Fuel Tank Capacity
2. Fuel Consumption
3. Fuel Autonomy

These three specifications are handy to know as they can help you calculate things like running costs and how often you might need to be running back and forth with those jerry cans!

Fuel Tank Capacity

Fuel tank capacity is the amount of fuel your pressure washer or heater can hold. For example, the Ehrle HD-series boast integrated diesel tanks of 25L. This means each HD steam cleaner, be it the 623 or 1140, holds 25L diesel for hot water cleaning.

 

Fuel Consumption

Fuel Consumption is simply how much fuel your pressure washer or heater uses over a given period of time.

Typically, on the Idropower website at least, this is measured in litres per hour. For example, the Wilms Val-6 uses 3.4 litres per hour. This means that if you gave the Val-6 3.5 litres of fuel, it would last just over an hour before it runs out.

Why is this useful to know?

Fuel consumption is useful for understanding and approximating how much a machine might cost. For example, the Wilms Val-6, as we mentioned, used 3.4 litres per hour of fuel. Let’s assume, for the sake of explanation, you have a fuel supplier selling heating oil suitable for the Val-6 at £1.50 per litre. You can, therefore, estimate the running cost of your Val-6 as £5.10 per hour of use.

 

Fuel Autonomy

Fuel autonomy is simply the continuous running time of a machine (such as a heater or pressure washer), should you brim the tank and leave it running without break.

How do you calculate fuel autonomy?

For example, the Master BV110 has the best fuel autonomy of the BV range: 21 hours. But how do they work this out? To work this out, they divide the fuel tank capacity by the fuel consumption rate. The BV110 has a tank capacity of 65 litres and a fuel consumption rate of 3.2 litres an hour. 65 divided by 3.2 equals 20.31 hours. Master, therefore, rounded up, because 21 looks better and is close enough for jazz.

Why is this useful to know?

Fuel autonomy is useful to know as it can help you calculate longer-term running costs and how often you might need to fill up. For instance, many of our heaters come with thermostats. Thermostats mean the heater will not keep running indefinitely but will attempt to turn off and on to regulate temperature. Therefore, if your heater is only running for 30 minutes every hour, your fuel autonomy will actually be double. For the BV110, this means 42 hours of running time. Let’s then assume you work 8-hour days across a 5-day week (sounds suspiciously white collar if you ask me!?), this means you’ll only need to refill the BV110 once a week.