PW questions i cannot find answers to

Good morning! First off, sorry, i know these types of questions are somewhat annoying, but i assure you that i have done TONS of youtube videos, reddit(probably a mistake), and google searches, however, for the life of me cannot figure out some of these issues. You dont have to know ALL the answers; an answer to any of these questions is greatly appreciated!

First off, prior to purchasing my machine I researched what type of machine specs would work best for sidewalks and driveways, and i found all sorts of different answers. What i gathered is that anything between 3200-4000PSI and nothing less than 3.5 gpm is what is needed to do driveway and sidewalk work, with higher range psi if im considering washing other things. Per statements like these “A 4000 PSI pressure washer is ideal for heavy equipment, concrete surfaces, brick walls, construction sites, stripping paint and lifting oil stains” I ended up purchasing a 4000psi 3.5gpm Simpson pressure washer (pw) and a 14inch surface cleaner(sc). My first question is

  1. Did I purchase a machine thats too strong?
    After getting the machine set up and getting familiar with it, i tried it out on a few random loose objects/surfaces around the house. What i found out is 4000 psi is DEFINITELY too much for certain surfaces, but is it too much for MOST surfaces?

Did i mess up by buying the wrong machine?
Ive read lots of solutions to having too much pressure, such as loosing the pressure valve(sounds risky) and buying different SC tips, and lowering the engine throttle(i dont know). Is it even safe for the machine to not run at full throttle? The most logical thing for me, is to buy bigger tips( also i feel like this would solves the issuse of my SC trying to become a helicopter) which brings up a different question. Ive seen about 30 different charts and im only about 65% im even reading the chart right anyway, but beisdes that it seems that every chart is way different from the last! Where i live, there isnt any PW dealers by besides stores like home depot or tractor supply, and not trying to be rude but…those arnt the people i would want to ask. Do you guys have any recommendations for places to purchase tips? The only places i see when i look it up are amazon and hardware stores(home depot and lowes do not carry any)

Basically to sum up my questions, did i buy the wrong machine?

Would my machine to useful for the type of work i want to do? If not what WOULD it be good for?

Would buying different tips solves my pressure issuse and if so, where can you find them?

Thank you for taking the time to read all that and again, ANY answers are greatly appreciated. Have a great day

You bought what u could afford to atart with.
Nothjng wrong with it. But soon enough you will find that an 8gpm is better

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Honestly, as someone fairly new to this business…you messed up by doing your research pretty much everywhere but here. GPM is going to be what you’re most worried about in terms of getting stuff done, hence why @Ikii said you’re going to want an 8 soon. Most everything you need to clean you can get the psi you need by using the right tips, but you want as much water flow as possible. So, knowing the inevitable replies coming, is returning that machine a possibility? I’m assuming it’s not since you describe haiving used it. If not, whether or not you messed up is irrelevant at this point. The question will be how do you maximize what you have until you can afford what you really need.

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You didn’t buy the wrong machine unless you could afford a 5.5gpm/8gpm with a tank and a trailer. I will never use more than 2500psi on residential concrete and even then some would say thats too much. Using PSI to clean instead of chemicals is a great way to damage property. You want to pre/post treat concrete with a 2-3% SH solution with some surfactant and let it do its job.

Next is the gpm. The amount of water your machine puts out is how much chemical you can apply and how much dirt you can relocate. If you have a 2 gpm machine and upgrade to a 4gpm, you’re putting out 50% more water allowing you to theoretically work 50% faster. I started out on the same machine you did and it worked fine for 2 months until I upgraded to a 5.5 and will never go back.

The nozzle sizes are what adjust your pressure. Use the search tab on this forum and find the appropriate nozzle sizes for your needs and buy a j rod. I never touch my throttle or my unloader valve while I’m working. It complicates things and will damage your machine. In order to put out 2250 psi you need size 2.5 nozzles in your surface cleaner. I’ll attach a chart at the bottom. On the top row is your desired psi. In the middle is the gpm of your machine. Since your surface cleaner has 2 nozzles, you divide the gpm by 2 and follow that number to the leftmost column where you will see your orifice size.

All of these answers are already on the forum if you use the search bar but I’d rather repeat whats already been said than have you make a mistake and ruin someone’s concrete.

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You can use the machine you have. It’s a starter machine to see if you’ll even like this line of work. Still use my 3.5gpm/4K psi multiple times a week in my small business.

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No one has any business starting a business with a homeowner grade equipment. Those that say you should are encouraging you to fail or don’t know any better. But this is a dead horse topic for sure.


You want 2502.5 nozzles. you can buy from any legit distributor. What part of country you live in?

Thank you, and yes definitely plan on upgrading later later!

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Thank you for the reply. No, unfortunately the machine is not returnable, but the way I see it, its a great machine and still has use. Just have to adjust and keep on truckin’.

Thank you so much, I really do appreciate the assistance.

After reading some of these comments, I most certainly do plan on upgrading to a higher gpm machine later. I think one of mistakes i definitely made was not knowing this fourm existed prior to beginning all this. If you dont mind, i do have a follow up question. I was searching around for places to purchase nozzles and i came across the term MEG nozzles a couple of times. Is that the type of nozzle that i should be looking for? Ive attached a screenshot of the ones i think i need according to what you suggested. What do you think?

Again, thank you soooo much for taking the time to help out. Have a great day.

Thank you. It is a “starter” machine that i hope to upgrade in the future, just gotta get my foot in the door, you know. If you dont mind me asking, since you own a machine with the same specs as mine, what kind of applications dp you still use your machine for?

I live in Texas.

Several places you can buy in TX. Yes you want the MEG nozzles preferably with the vanes, if anyone has them.

Check this link out, its to a previous post I made and I think it’ll cover most of what you are looking for. But let me know if there’s anything else you’d like to know about my little setup.

Basic Truck Bed Build - Economy Style - Less than pretty