Unloader question

I work residential concrete using the classic 19" surface cleaner with a pressure pro 4040, at 4 gpm and 4000 psi. Age of concrete 4 to 14 years and I think it is very poor.

Like many others on the forum, I have excessive sand from the concrete in the rinse water.

Various nozzles I used are 25 degree 2.0, 2.25 and 2.5.

A suggestion I like is reducing pressure to 3000 using the unloader and leaving it there.

I'm told I may loose a little flow but that it won't hurt the pressure washer.

Am I on the right track?

reduce pressure with orifice size using different nozzles... not messing with unloader... Unloaders are supposed to be set and forget

Can go to 40 degrees if you need less impact... 15's if you need more..

run you machine at a lower RPM will give you lower pressure. 4000psi on concrete. Wow! not surprising you are taking the surface off the concrete and generating a lot of sand.

Larger nozzles-

Look at the nozzle chart found everywhere, lower your pressure with larger orifice nozzles.

I have to lower pressure on a lot of properties, new and old as many concrete contractors add water to the mix and it weakens the concrete almost by half in a lot of cases and most don't see it happening as not everyone involved in the job is there when they pour and start working the concrete. Sometimes they put a hose into the truck, sometimes a hose into the pour as it is pouring, there are more ways that those guys are sneaky to make the concrete easier to work and most don't know how it weakens the concrete by adding water, some don't care as long as they do their job and get paid.

I have to lower the pressure to 2000psi, once in a while down to 1500psi, always do tests to see how strong the concrete is and you will be ok.

If you don't want to change out the nozzles all the time, get an extra spray bar with the other nozzles in it, if you can afford it, another surface cleaner so you just grab the machine for the job based on the strength of the concrete.

Thanks guys, that was easy. Nozzles win.

I just ordered 3.0 and 3.5 nozzle sets at 25 degrees. After a little trial and error I'll order a set at 45 degrees for my back up surface cleaner (hammerhead).

Special thanks to Chris in Texas that nailed the problem.

It's his detailed info that was most helpful.

Now you are learning. Always adjust your pressure with larger orifice nozzles. If you try to do it with your unloader you just restrict your flow (GPM) through the nozzle thus slowing down your work speed. GPM = work speed.