How to Adjust Unloader Valve on Pressure Washer

The unloader in any pressure washer controls high water pressure, which is the reason why it sometimes needs adjustment. If the unloader is left unadjusted, the machine won’t be able to apply the desired pressure for any specific application. 

As this adjustment has to be done from time to time, you must know how to adjust unloader valve on pressure washer. The process is quite easy, but a bit difficult to understand. As soon as you understand the mechanism, and how you are helping the unit to adjust its setting, you will master this adjustment.

how to adjust the unloader valve on a pressure washer

Why an Unloader Valve is Needed for a Pressure Washer?

Water has to pass through this unloader to come out of the nozzle. The unloader directs the water to the inlet valve to make sure the water circulation is smooth.

To simply put, an unloader valve is basically a pressure regulator that controls the direction of the water flow in the pump. It helps the water to pass through the pressure system, and makes it easier to come out of the spray gun.

But when the gun isn’t spraying water, the valve moves the pressure outlet towards the inlet to redirect water. Inside the washer system, it circulates continuously through the pump, and keeps coming back to the unloader inlet.

Purpose of Adjusting the Unloader Valve

Pressure washers can go up to 3500 PSI, which is considered very high. Not all applications would require such high water pressure. If you apply too much water pressure to wash your car or motorbike, the excessive pressure will damage materials that cannot withstand the pressure.

On the other hand, high pressure is needed for cleaning driveways, flooring systems, and concrete walls. So, you will have to increase the water pressure to do the cleaning task more effectively. 

The spring tension on the valve really helps to get the maximum pressure on the spray gun, and minimize it after releasing the trigger. Minimizing the pressure, you can wash screens, cars, furniture, etc. applications without causing any damage to the surface.

To get such full control on your pressure washer, you must know how to adjust an unloader valve on a generac pressure washer.

Preparation before Adjusting the Unloader Valve

Regardless of the pressure washer unit, the steps below will be the same for all models. Before attempting how to adjust an unloader valve on a craftsman pressure washer, be sure to ensure these –

  • Be sure to turn the pressure washer motor on while adjusting the unloader.
  • Set the motor at 3700 RPM before the load, and 3400 RPM after the load.
  • Remove lock nuts from the valve, and turn off the pressure adjusting knob. A simple spinning would do the trick.
  • Further, remove the spring and washer from the valve. You should see a threaded piston with two locknuts.
  • Now, use a wrench to lock these two nuts. Make sure the nuts are three threads off the bottom.
  • Put washer, spring, and nut back as these were before.
  • Finally, clip the pressure gauge between the hose and pump. You should be able to see both these while adjusting the unloader valve.
How to Adjust Unloader Valve on Pressure Washer

How to Adjust Unloader Valve on Pressure Washer?

Don’t rush while following the steps below. If you do exactly the same as stated below, you should be able to adjust the unloader as per the applications require.

Step 1 – Get Rid of Stuck Air

Make sure the pressure washer outlet valve is turned on. This will make the water flow, and push the air that got stuck inside the nozzle.

Step 2 – Reach the Maximum Pressure

Slow tighten the pressure spring while keeping an eye on the gauge. Pull the trigger, and see if the pressure point reaches the maximum pressure that you would need, which is 3700 RPM.

The pressure spike should stay idle at 6-9% after disengaging the trigger.

Step 3 – Ensuring the Spike at 10%

If you fail to maintain the spike at 10%, try moving the nuts to hit this range. But, if the spike cannot make it there, then you will have to unlock the nuts, spring, and washer to try again.

Step 4 – Let go the Unloader

Now, let go of the unloader for 15-20 times. It will help to break in the unloader valve, and make sure the valve doesn’t hang up. Even if you set the pressure at 3500 PSI, it can go up to 3800 PSI. Make sure, the pressure isn’t more than that.

Step 5 – Put Things Back Together

Your pressure washer unloader valve should be adjusted if you have done properly as following the steps.  Put back the lock nuts, washer, and spring to their location. Check if the pressure gauge is showing the same readings or not. Secure the lock nut of the piston rod and cap of the adjusting knob is everything is as it should be.

Thing that You Shouldn’t Do

Be sure not to crank down on the pressure spring. This action won’t generate more pressure engaging the trigger. Oppositely, it can damage the pressure washer when there’s a high-pressure spike when you disengage the pressure gun.

Final Words

Once you figure out how to adjust unloader valve on pressure washer, you will get things done more efficiently. This will allow you to deliver the right pressure for washing specific applications. The unloader might require adjusting time to time if you use it for commercial purposes, but it won’t take much time after you adjust it for 3-5 times.

Always check if the gauge is showing the readings needed for that specific washing project or not.

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