Adjusting the Unloader Valve on Pressure Washers

Pressure washers are common in many homes today. This is because they help with removing the dirt and grime with ease compared to some other methods you might have used before. If you end up with the right pressure washer, cleaning just got easier. To make this happen, the unloader valve on your pressure washer should be within the right setting. 

It might not be the simplest thing to handle, but today we try to simplify it. Let us look at what the unloader valve is all about and how you can achieve the best settings below. 

So, why is an unloader valve important?

Before you can even start with the process on how to set the unloader valve, first you need to understand its purpose. Well, an unloader valve is simply a pressure regulator for your pressure washer. It will ensure that it directs the flow of water into the pumps. It also helps the water get through the pressure washer so that it can come out of the spray gun at the desired pressure. 

Whenever you are not spraying the water from the gun, this unloader valve will redirect this water to a safe pressure outlet. By doing this, it will be circulating through the washer pumps and get the water ready for use again when you start using the spray gun. 

Why you need to adjust the unloader valve 

The pressure level range for most pressure washers can be quite high. Some will have up to 3500PSI in terms of pressure delivery capability. Such pressure might not be ideal for some applications such as washing your car. For this reason, it would be great to regulate the pressure to a point where it is safe for your given application. 

The flooring systems would need higher pressures so that the embedded grime and dirt can come off easily. It is always a good idea to try the pressure washer on a small area before going all out to use it for cleaning the whole area. Having a sudden spike in pressure can always be dangerous and can also damage the surface or worse hurt someone. 

Having the unloader valve correctly adjusted will help a lot for those who need to use the pressure washer for multiple applications. It is possible to use the unloader valve to adjust the pressure so that you can wash the car windows, body, and tires at different pressures. As you can see, having a pressure washer with the correctly adjusted unloader valve makes it quite versatile. 

Process of Adjusting the Unloader Valve 

Now that you know more about the unloader valve, it is about time we moved on to how to adjust it. Depending on the pressure washer, the process is always relatively the same. As much as there might be some slight differences, you should always find it possible to make the adjustments. 


  • When you have to adjust the valve, keep the motor of the washer running. Always make sure it is set to the right rpm. Normally, it would be 3700 before having a load and then 3400 when loaded. 
  • You can now remove the nylon insert lock that is on the unloader valve. Proceed to shut off the knob for adjusting the pressure. 
  • This is then followed by removing the spring and washer. This leaves you with a threaded piston rod, which contains two lock nuts. 
  • Get yourself a wrench to lock these two nuts up to three threads from the bottom. Once you are done, put the washer, but, and spring as they were before. 
  • Proceed to clip the pressure between the pump and pressure hose in a way that allows to see them whenever you adjust the knob or trigger the gun. 
  • At this point, let out the air from the gun and then proceed to turn on the water to flow. 
  • While keeping an eye on the washer gauge, start to tighten the spring. You need to observe the flow of water until you reach the point when the maximum pressure of the gun is engaged. When you let go the trigger, it is expected that the pressure spike would be around six to nine percent. If that is not the case, keep adjusting until you get it close enough. This is the ideal point and you should stop adjusting. 
  • Once you have the right adjustment, you can now go ahead to place the spring, washer and knob. Check again the gauge just to ensure you are getting the right readings. 
  • Finally, you can now screw the nylon lock nut back to its position and cap back onto the adjusting knob. 


As you can see, the process does not have to be hard. With a few adjustments, it should be possible to enjoy using the pressure washer. You can always follow the manufacturer’s guide if they have given you the process on how to adjust the unloader valve. 

Leave a Reply

Your email address will not be published. Required fields are marked *