How to Adjust the Unloader Valve on Your Pressure Washer

Some people believe that you can turn an unloader valve to reduce the pressure output of your machine. This is not the correct way to adjust pressure. The unloader valve is designed to allow water to bypass through the pump when the trigger is not engaged. If you turn the unloader to reduce pressure, you are also reducing GPM, and reducing cleaning power. Cleaning power = GPM X PSI. So if you have a machine that runs at 4 GPM and 4000 PSI, your cleaning power is 16000. If you change your nozzle to a 2000 PSI nozzle, your machine is still going to output 4 GPM. Your cleaning power is 8000. Lets say that turning the unloader down to 2000 PSI will reduce your GPM on this machine to 3 GPM. This would result in a cleaning power of 6000. Less power means longer cleaning time. Longer cleaning time means higher labor costs. Nozzles are less expensive than labor. Messing with your unloader valve can also put undo wear on your machine. Nozzles are cheaper than buying a new machine. Do it the right way, and life will be easier!

[bryanmontgomery]

Tip size plays a huge role in this adjustment, if the tip is too large you will get the high differentiation, if the tip is too small, your differentiation will be much lower. I recommend using 0.5 gpm below the max rating of a 4.0 gpm and smaller, 1.0 gpm smaller above that to a 10 gpm machine.

[trentclark]

Awesome video. Looks like I need to rig up a gauge & go experimenting with my equipment. Thanks again!

[petrus]

now you got me wanting to do your course >:D
- Thanks for the great content

[thDevil]

I have a belt driven 3500psi/3.5gallon washer. I have adjusted the unloader to the point where I have 2500psi. I reduced it to wash cars and to lower the gallons per minute. Will having this adjusted at low settings damage the engine or pump? Mind you I have a bypass hose from the unloader that shoots back into my water tank.

[budgetpoolcare]

Dosnt it all depend on the nozzle size your using as well?

[spagsketti]

Thanks for the tip This will help me in my adjustments .

[kevinulmer]

I've seen videos that have unloaders that dump the water automatically when your not on the trigger. How do I set that

[yvesn]

Thanks for your video. Wonder how to dismantle the valve on a Karcher K1900. Any cues?

[HappyHands.]

Does lowering the pressure make the pump last any longer?

[aurafangz]

Hello Mike, do you recommend stainless steel fittings for the pressure gauge for higher PSI machines?

[victorgomez]

Y got two hoses of 50 feet, can I put them together?
Where is recommended for put the pressure valve, on the machine or in the end of the hose?

[danielcj]

I added a pressure gauge to my pressure washer, I installed it after the pump but before the unloader.. is that OK? Will it show accurate pressure? Or should I have installed it after the unloader?

[kramynke]

What if my machine is building pressure and makes it very difficult to start? Where would I start troubleshooting?

[aurafangz]

I have tried to adjust the unloader on my 4gpm 4000PPSI machine but unfortunately with the unloader turned all the way up I get a reading of 3400PSI (when running) and a spike of 3700. Could I be doing something wrong to not be able to reach the 4000PSI max pressure?

[anextday]

Can you do a video showing how to do adjust the flow actuated type...thanks

[jessenelliott]

So I don’t want to have a pressure spike and I want my washer to be running just below it’s maximum pressure yes?

[darealsmotpoker]

When setting your unloader what tip should be in your wand

[leesire]

Is it ok to leave the washer running while not using it. Or do you constantly have to be spraying? I have a Dewalt. Psi 3200 I think

[jamesjackson]

I have a ryobi 3300psi. I have to start it with the trigger pulled and when i let off the trigger it loads up pressure untile it stalls the engine. Bad unloader?

[mikehrynyk]

Why when you release the trigger the motor stops running, or trying to start motor…. Can’t pull the cord easily