[Mudskipper]

I'm a newb to how the valve works. Is this also called the unloader valve ? I have a AAA pump on a Honda GX270, 4000 psi and 3.5 gpm. I was told that turning this knob will lower the pressure so a can have less pressure using my 20 inch BE whirl away surface cleaner.......does this also lower my GPM ? Or just lower the pressure/psi ? I have read that I should lower my pressure when on concrete. I don't want to lower GPM because according to nearly everyone I have too low a GPM for 20 inch surface cleaner. I just did my driveway (170 feet), sidewalks and curbs and it worked perfectly. They were nasty as I live in Florida. Thanks

 

[sledman8002002]

Welcome to the forum Mudskipper!

does this also lower my GPM ?

Not something I've ever thouight about before so I cant say for sure, but I would think likely. But perhaps not?
I can only suggest a simple R&D test, take 2 empty 5 gallon pails and run the PW with surface cleaner attached and sitting inside the pail (if it'll fit?).
Run it once with the pressure up in one pail and pressure down in the second. Run them both for 60 seconds.
With accurate timing, doing so should give you a pretty good idea on the GPM difference, (if there is any).
Hope this helps.

 

[Mudskipper]

Welcome to the forum Mudskipper!

Not something I've ever thouight about before so I cant say for sure, but I would think likely. But perhaps not?
I can only suggest a simple R&D test, take 2 empty 5 gallon pails and run the PW with surface cleaner attached and sitting inside the pail (if it'll fit?).
Run it once with the pressure up in one pail and pressure down in the second. Run them both for 60 seconds.
With accurate timing, doing so should give you a pretty good idea on the GPM difference, (if there is any).
Hope this helps.

I'm going to assume you've never owned a 5 gallon pail/bucket. They are under 12 inches wide, and you read that my surface cleaner is 20 inches wide. If you've never looked under a surface cleaner the spray tips are at the outer edges. Lying it on a bucket would not remotely work. This isn't a question that someone that is familiar with pressure washers can't answer. It's simple and basic question.

 

[TBR]

Turning the unloader valve clockwise will increase the pressure, ccw will decrease the pressure. The GPM doesn't change.

 

[Mudskipper]

Turning the unloader valve clockwise will increase the pressure, ccw will decrease the pressure. The GPM doesn't change.

Thank you ! I have turned it counter CW and can see on my gauge that the pressure lowers , but it would make sense that turning the loader down to decrease pressure would also decrease GPM since its closing the valve, unless it's opening it to decrease pressure.......but I couldn't find that in writing anywhere online, no mention of GPM change anywhere.

 

[TBR]

Your GPM is calculated by piston size, stroke, and Rpm. Your unloader sets the output pressure.

 

[sledman8002002]

They are under 12 inches wide, and you read that my surface cleaner is 20 inches wide

Yep, missed the mark on that one. Never had reason to measure a pails diameter before.