The only way you change the flow rate of a pump is by either restricting the outlet or reduce the rpm of the engine. Flow is displacement of the pump pistons will remain the same at a given speed. Reduce the rpm equals reduced flow.
gpm remains constant, tips just change pressure. However, flow thru the pressure hose will diminish if you put a high pressure tip in. The water is still being produced by the pump, it is just bypassing thru the unloader.
The pump will continue to put out a constant flow, but turning the pressure down at the unloader results in the unloader bypassing a certain amount to reduce the flow (and thus pressure) at the gun.
Here: play around with this calculator for awhile to see how the flow rate, orifice size, and pressure all relate. You can’t reduce pressure without either going to a larger orifice, or reducing the flow.
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I good way to see that you’re loosing flow out of the gun when adjusting the unloader is to pull your bypass hose out of the tank. As already mentioned if you lower psi you’ll bypass more water. Squeeze the gun, adjust the unloader, and watch how the bypass hose bypasses more water even though you’re on the gun.
Set the unloader and forget about it. You’ll get max efficiency out of your washer that way.
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