Setting Unloader to lower psi

Hey guys, tried searching around before writing this. Just have a quick question i need some confirming.

I have a machine thats a 4 gpm, 4k psi. I find most of the time its way too much pressure. If i lower the pressure on the unloader and set it say 3500 psi, will i lose gpm or will it just lower the psi but keep gpm intact?

Any help much appreciated.

Set the unloader properly and leave it. You adjust pressure via nozzle selection.


Always lower your pressure by using different nozzles or tips. Never lower with the unloader. Like never ever.


Just an update. When i mean lowering with the unloader i do not mean just twisting it manually, i mean actually setting it at 3500 psi

Nozzles! Leave the unloader set properly.


The unloader should be set with the amount of hose you intend to run most often and it should be set to bypass just a trickle. The psi it’s set at is not important really. If you want to lower the psi use a different nozzle


Yeah thats what i figured. Was just trying to see what other ideas i could do.

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You will lose flow. Pressure sensitive unloaders should be bypassing about 5% of your flow rate to protect the pump :+1:t2: Screwing it in will increase bypass and therefore reduce flow.

If you’ve screwed it in or out - best to set it again.

On a 4@4 the “spike” of the needle movement on your pressure gauge (when you let off the trigger) should be at 4000psi (or just a bit over) no more.

Then use the chart previously posted and buy the correct nozzles to lower the pressure - but not the very important flow :ok_hand:t2:

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Interesting. When i bought my 5.5/3500 I asked if the unloader needed to be set and they said it was already done at the factory.

When off the trigger my bypass hose to the tank really blasts, I’d say it’s at least half flow if not more. Maybe I need to adjust it a bit?


@dcbrock An unloader diverts full flow during bypass. Setting the unloader only affects flow directed through the high pressure outlet. If your bypass water is blasting out then increase the bypass hose size and/or make sure it is exiting near the bottom of the tank. 3/8” hose should be sufficient

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The blast is normal when off the trigger :+1:t2:

The bypass when ON the trigger should be a trickle/5%.

I found this old webpage, 9 years old - but it’s still pretty good…