How to Adjust Unloader Valve on Pressure Washer

If you buy an item via links on this page, we may earn a commission. Our editorial content is not influenced by commissions. Read the full disclosure.

In order to change the pressure level of your pressure washer, you need to learn how to adjust unloader valve on pressure washer. This guide will show you how.

You can’t use the same pressure level when cleaning different parts of your home. There are some areas wherein you have to use weaker pressure than others. That’s where the unloader valve comes in. The unloader valve is a small part of a pressure washer that plays a big role in controlling the strength of the water coming out of your pressure washer.

Of course, you need to learn how to adjust unloader valve on pressure washer. This guide will teach you all about adjusting unloader valve on pressure washer.

How the Unloader Valve Works

Before learning how to adjust unloader valve on pressure washer, it’s important to first understand how the unloader valve works. To know that, you should first know the other parts of the pressure washer too. 

Basically, you have the unloader valve, the nozzle the pressure gun, and the inlet valve. When the water comes out from the pump, it goes to the pressure gun. Before that though, it goes through the unloader valve. The unloader valve is what will direct the water to the inlet valve so that the circulation of water is smooth.

Consequently, you need a reliable and powerful high-pressure hose. Click HERE to see the top options!

As you can see, the unloader valve controls the amount of water that flows out. That is why it is important to know how to set unloader valve on pressure washer. Now that you know the important parts related to the unloader valve and how the unloader valve works, we can go on to the steps on how to adjust unloader valve on a pressure washer

How to Adjust Unloader Valve on Pressure Washer Machine

Fortunately, learning how to adjust unloader valve on pressure washer is really easy and will only require you to know a few steps. 

Here are a few steps that you need to take note of:

  1. Maintain a running pressure washer with 3700 rpm before the load and 3400 rpm under it.
  2. Disconnect the nylon lock nuts from the valve and turn off the pressure adjuster knob.
  3. Take out the washer bolts and springs that are attached to the unloader valve.
  4. Use a wrench to tighten the two nuts on the piston.
  5. Put back all the parts together and use a pressure gauge assembly to connect the hose and the pump.

These five steps can be considered as the preliminary steps that you take before you do the actual adjusting pressure washers. From here, we can move on to the actual steps on how to adjust a pressure relief valve on a pressure washer. 

  1. Take the pressure gun and release all the excess air out.
  2. Turn on the water in the pressure washer.
  3. Tighten the spring on the gauge and engage the trigger.
  4. Engage the trigger until it reaches its max pressure then disengage it to 9 percent.
  5. Break the unloader a few times to break it in.
  6. When you have the right adjustment, place the springs, washer, and knob back in.
  7. Double check the settings to see if everything is ideal.
  8. When everything is ready, attach the nylon nuts back in place.

Now, take note that there could be some times when the pressure won’t reach less than 10% in step 4. If this is the case, all you have to do is just keep on fiddling with the nuts until it reaches this percentage. While 9 percent is the ideal percentage, you don’t need to be so stiff on the number. If it reaches somewhere between the range of 6 to 9 percent, then it’s already good to go. 


Sure, this may seem like a pretty complicated thing to do when you read the steps on the onset. However, it’ll be much easier when you’re actually in front of your pressure washer and doing it already. Once you learn how to adjust unloader valve on pressure washer and try it out for yourself, it won’t be so difficult. In fact, it’ll seem like such a simple task that anyone can do. 

That said, we highly recommend that while you’re working on your pressure washer, keep this guide at the side so that you can use it as your reference when you’re doing the actual adjustment of the unloader valve. That’ll make things much easier and much quicker.

TOP 5 most viewed articles in month

In compiling a top-5 list of this month's most popular articles:

Mattie Keyes

Hi there! This is Mattie. When I am not making DIY projects for my house, I spend most of my time researching and writing reviews of different products that you can buy online. I am an office worker turn full-time blogger, and I hope to help other homeowners like me on how to improve and reinvent your home using the best ideas and equipment.