Pressure washers are sold with many accessories included, the most important of which are nozzles. But how do they work? What are the differences between them? Why are there so many?
- Why Should I Care
- Nozzles by Angle
- Other Nozzles
- Tips and Tricks
- The Working Principles of Nozzles
Don’t be deceived by their size! Even though they are the smallest item in the box, using them correctly is crucial.
An incorrect choice of a nozzle can lead to splashing water aimlessly over a stain without any results or cutting a hole into your house. Read along to avoid just that!
Why Should I Care
If there is one message you should take away from this article, it is the following:
Every nozzle has its purpose and is not interchangeable!
Each pressure washer has a pump, which is run by an engine, with a set of specs given by its design. While these are set in stone, a water stream which the pump creates is not – it is fluid and malleable.
To modify the water stream, its speed, pressure upon impact and the area it covers, we use nozzles. Therefore, by using different nozzles, you can drastically change the features of the stream, which will affect what they are and aren’t suitable for.
To fully appreciate how and why, we present an extensive explanation at the end of this article, which should not be considered a mandatory reading, but may be useful in your future endeavors.
Nozzles by Angle
For now, in short form:
The smaller the angle the stream is spread at, the higher its pressure is upon impact. Or in other words, the more intense it will be.
Among pressure washers, you will commonly find up to 6 different nozzles which vary by the angle of their opening. These are 0°, 15°, 25°, 40°, 65° (soap), and a so-called Turbo. Each of these nozzles is specifically colored, which has become an industry standard in the US.
Please note that it is uncommon to see all nozzles included with a single pressure washer. When choosing a pressure washer, make sure to check out its product sheet to see which nozzles are included.
The 0° fan nozzle is suited for cutting, or chipping. It has enough power to damage paint, wood and other soft and malleable surfaces. It is also somewhat impractical due to its limited range (axial). It is commonly recommended for tough stains on metal or concrete surfaces.
It can also be used on other surfaces, with a lot of caution and at a long distance – we recommend choosing a different nozzle if possible. Any use of this nozzle should be tested beforehand on a small area of the target surface, to check if it leaves any damage, before proceeding further.
The 15° fan nozzle, often called the chiseling nozzle, is great for chiseling paint when used at a 45° angle. Consequently, this makes it still way more powerful than necessary for common cleaning tasks.
It should be used with great caution on surfaces beyond concrete and metal. Any use of this nozzle should be tested beforehand on a small area of the target surface to check if it leaves any damage, before proceeding further.
The 25° fan nozzle is commonly called the flushing nozzle. In the order presented herein, this is the first nozzle suitable for surface cleaning, though its use should be limited to metal and concrete.
Other surfaces should be approached with caution. Any use of this nozzle should be tested beforehand on a small area of the target surface, to check if it leaves any damage, before proceeding further.
The most common, 40° fan nozzle, dubbed the wash nozzle, is the number one choice for cleaning most surfaces. While caution should always be taken when using pressure washers, it is commonly assumed to be safe.
Exceptions are boats and RVs. Any use of this nozzle should be tested beforehand on a small area of the target surface, to check if it leaves any damage, before proceeding further.
65° Soap (Black or Blue)
The 65° fan nozzle, also called the soap nozzle, is used for what its name suggests – applying soap (detergent) to a surface.
This would be commonly done before the cleaning takes place. The nozzle applies minimal pressure and is considered safe to use on all surfaces.
The turbo nozzle is less common, but cleverly designed. It applies the force of a 0° nozzle, in a 25° area and adds rotation. It is reported to achieve almost the same pressure upon impact as the 0° nozzle, but covers a significantly larger, cone-shaped area.
The same precautions apply as for the red nozzle. Any use of this nozzle should be tested beforehand on a small area of the target surface, to check if it leaves any damage, before proceeding further.
Check out the following videos to see the nozzles in action:
Long-range nozzles do exactly what their name suggests – they increase the reach of the stream, usually up to 30 ft.
You should follow the red nozzle precautions when using these.
Variable Nozzles (5-in-1, 7-in-1, etc.)
Variable nozzles allow the user to manually adjust the angle of the opening of the nozzle. They commonly utilize a rotary mechanism.
Most variable nozzles are model specific and also have pressure limits which must not be exceeded.
Flow Control Valve
Flow control valves are not exactly nozzles – they are sort of pre-nozzles which allow you to further control the inner diameter of the pressure washer and give you some additional control over the stream. They are usually installed between the trigger gun and the wand.
Rollover nozzles are attachments which allow you to flip between two or more nozzles by simply rotating the attachment.
They may save some hassle, though we suggest you pay attention to their compatibility, since they are an extra layer which may fly off under pressure.
Second Story Nozzle Kit
Second story nozzles do exactly what their names suggest – they reach the second story of your typical US suburb house. The set consists of two nozzles that differ by their inner diameter, both of which have been classified as 0°.
So, why would you need an extra pair 0° nozzles? For their unique, range-oriented design!
Both are designed so that their stream doesn’t disperse into a mist as fast as a 0° tip would. And one of the two nozzles is even designed to spray soap. Therefore, the second story kit can be used to clean an entire face of a two-story house comfortably, keeping both of your feet on your lawn.
Foam cannons are a play on the soap nozzle. The detergent, or “foam reagent”, is placed into a container, which is directly attached to the nozzle.
The effect is a much denser, foam-like output, compared to the soap nozzle.
Tips and Tricks
If You Are Buying a Pressure Washer
- Always check the product sheet to see which nozzles are included.
- Nozzles are cheap. To avoid wasting time, I’d suggest checking out the product sheet for missing nozzles and adding them into your basket right away.
- Nozzles sometimes are, but in general are not cross-compatible. To avoid trouble, buy nozzles made for your specific model. Compatibility may also be indicated by the diameter of the nozzle. However, keep in mind that the same diameter may not guarantee that the nozzle will fit exactly your product (though in most cases, it probably will).
- Beware if you are buying spare nozzles from overseas, since it is not guaranteed that the colors necessarily mean the same as in the US.
- Check nozzles for pressure limits to ensure that they won’t fly off and destroy your windshield.
- You may want to consider buying spare nozzles ahead, since they tend to get lost when you need them the most.
- Consider buying a spare nozzle cleaning tool if you come across it.
From time to time, your nozzles need to be cleaned. This may be indicated by a loss of pressure, or even pulsing of the water stream. In such cases, follow these instructions.
- Turn off your pressure washer and its water supply.
- Relieve any pressure left in the spray gun by triggering it, then lock it off.
- Remove the nozzle from the spray gun.
- Use a nozzle cleaning tool (if provided), an open paper clip, or a wire and move it back and forth through the nozzle to unclog it.
- Run water through the nozzle with a garden hose before applying it back onto the pressure washer.
The Working Principles of Nozzles
Warning: For interested readers only! The following section explains how nozzles work and why we use them in the first place in some depth.
On the Benefits of Small Holes
To build up some intuition, let’s start with a simple question: Why would you want to close off your pressure washer with such a tiny opening?
In equally simple terms, the answer would be: To greatly increase the velocity of the stream without any effort at all. Let me explain
An engine of a pressure washer runs a pump. This part does all the heavy lifting and creates the immense internal pressure of up to 4000+ PSI. Keep an eye out for our upcoming article to learn all about them.
The pump creates a flow of water – the volume of water that is moved through the diameter of a pipe at any given point, measured in gallons per minute (GPM). This is known as the volumetric flow rate (opens in a new tab), though is commonly dubbed water flow and on our site, will be commonly referred to as the GPM. However, for the purpose of this article, we will stick to flow rate.
Distinction must be made between the flow rate and the actual speed of the stream (flow velocity – opens in a new tab), which would be measured in units such as mph, since the two aren’t the same:
It is easier to spill an ounce of water by turning a glass upside down, then emptying it by a straw. In these terms, it requires a higher velocity to achieve the same flow rate in a constrained diameter.
So far makes sense? Good, now for the next step.
The pump pushes water forward with same force regardless of how far from the engine it is, since it behaves as a continuum (opens in a new tab), e.g., the entire body of water behaves as “one thing” being pushed forward. The rate at which its volume travels — the flow rate — must therefore also remain the same throughout the entire network of tubes.
This has a surprising consequence. Since the rate at which VOLUME travels must stay CONSTANT, if we constrain the diameter of the tube, it’s WATERFRONT must now flow FASTER to maintain the flow rate! Now isn’t that cool?
Therefore, by closing off the very tip of the tubing, we greatly increase the speed at which the water exits it, WITHOUT ANY ADDED WORK!
This gives us an even faster water stream, easily by a factor of 10 or more, which applies great pressure, force per surface area, upon landing – for example on a stain.
Calming the Stream
Now imagine trying to clean your pavement with a stream which has a diameter of a pinhole. Not exactly effective, right? We can easily add an angle to the slope of the opening, but what effect will it have on the stream?
After exiting the nozzle, the water stream doesn’t obey the constraint of a constant flow rate applied in a continuum. There is no force pushing it continuously anymore. It is rather ejected from the nozzle – A much more accurate view would be imagining the stream as a series of bullets.
With a pinhole shaped nozzle, a mass of water, given by its volume – or in our analogy, a series of water bullets, all impact a single spot.
If we angle the slope of the nozzle and let the water stream “spread”, we are still ejecting the same volume (hence mass) of water, or the same amount of water bullets, but they are now landing in different spots. The same overall force is exerted by the stream, but it is spread across a wider area. Therefore, there is now less pressure applied upon impact. In our terms, fewer bullets are hitting each spot.
Intuitively, the fewer bullets hit one spot, the smaller the hole they leave behind. Therefore, apart from achieving a wider stream, the nozzle also modifies the pressure it exerts upon impact. See the picture below for illustration.
Note 1: By this simplification – the bullet model, we have more accurately described what happens upon impact. However, the nozzle is a region where the stream still acts as a continuum, right before it escapes into “free space”. Therefore, by opening up its angle, some speed is actually lost via the mechanism described in the previous section.
Note 2: Beware of pressure! It must be distinguished which pressure is referred to when talking about water – static or dynamic, and where the pressure is measured. Note that in this article, we are referring to the pressure upon impact – as do other sources when talking about nozzles, not pressure inside the device, which is constant, nor the pressure measured at the tip of the nozzle, which would in fact decrease when the diameter is narrowed due to the so-called Venturi effect (opens in a new tab). Most importantly, it is therefore not the same pressure as the PSI spec given in our product sheets, which usually refers to the pressure on initial trigger pull.
Note 3: Regardless of which nozzle you use, the driving force behind the water stream and what ultimately decides its power is the pressure washer’s pump. The nozzle is but a simple physics trick that allows us to milk the washer’s power dry. Therefore, the list of included nozzles is certainly not an indicator of how well your pressure washer will clean.
In conclusion, we have learned why and how nozzles are classified by the angle of their opening. Consequently, each nozzle applies different pressure on a surface – the smaller the angle, the greater the pressure. For this reason, each nozzle has its specific advantages and limitations.
There are several “special” nozzles, which have been described by their use. I have also added several tips and tricks, including a purchase guide on nozzles and a quick guide on when and how to clean your nozzles. Hopefully, this is all you will ever need to know about nozzles.