Pressure needed for commercial work

Hi all,

We’re thinking of moving more heavily into commercial pressure washing, ie, adding a hot water setup. We currently have a 3,000psi 8gpm cold skid, and I really can’t imagine going down in flow rate, so I’m looking at 8gpm hot water skids.

My question is about pressure needed: Shopping around I notice that there are plenty of 8gpm 3,500psi setups available, but much fewer options above 3,500psi. At least, not without a big jump in price. So, typically running 200ft of 3/8" hose, does a 3,500 pump generally provide enough pressure for commercial work?


Commercial what? Buildings, concrete, construction clean up? I wash apartments with 8@3000. Pressire pro and some vendors sell 8@3500 wirh Honda gx690 but it is just marketing gimmicks and lies. You cant get both from 21 hp. Most add on hot boxes won’t get 8gpm hot enough for oil and grease if you are thinking concrete and parking decks. Basically, commercial can mean a lot of things and 8@3000 can clean 99% of it.

I guess I’m really talking about commercial flatwork. Dumpster pads, commercial sidewalks, gas stations… that kind of thing. Yes, heat for the grease, gum, etc.

So would you think that 3,000 psi would be enough pressure for those things, assuming the water was hot enough?

Which leads to the obvious question: if most hotboxes can’t get the water hot enough at 8gpm, does that make a valid case for going down in volume?

(And yeah, I’ve read your posts about the GX690 not being able to deliver 8@3,500, and I think you have a point. Not enough hp for that to be the real output.)

I mean, when I say “a valid case”, it’s because I’ve become quite addicted to the flow of an 8gpm. My mind flashes back to my 4gpm days, walking slowly behind an 18" SC. That was fine on a small residential driveway, but it doesn’t sound very efficient when we might be talking about large areas to be cleaned. But is that just reality? In other words, if you want 8gpm, and if you want it hot enough, you need to spend a lot more than “Pressure-Pro Prices.”

I have no advice on concrete. I try to talk homeowners out of doing driveways. What I know about hotboxes is only what I have read. I had a hot water unit back in 1998 but cut the skid in half after a few months and sold the hot box. There may very well be an add on hot box that will work. Bob at or Paul K would be the ones to ask. All of it is pretty much drop shipped from Barons probably so go with who you like the most.

OK, thanks for your reply. I appreciate you taking the time.

I gotta know: “I try to talk homeowners out of doing driveways”? :thinking: Do tell…

I don’t do houses much anymore but when weI do there isn’t much time for add ons. I tell homeowners driveways are like roofs. Don’t waste money cleaning then unless you are trying to sell your house.

Fair enough. Not having time for add-ons is nothing to sneeze at.

Farleys coil shop 479-524-9594. $3500.00 - to $4,000.00 for a 3500 @ 9 gpm, heats my water to over 220 F. They are big vertical units 5+ feet tall. Good luck

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So, Pressure Pro has two offerings, one 8gpm@3000 and one 8gpm@3500 with the same engine. So what it the difference making up that additional 500 psi?

The 8gpm 3000 uses GX630 vs the gsx 690 on the 3500.

I noticed that the same engine/pump combination would be rated 500psi lower if it was also driving a 115V generator for the burner. I guess it must load the engine down just a little more. Could that be what you’re seeing?

Meaning, 115V burner vs 12V burner.

No. You want the 3500 though because between the heater and the hose going to lose about 700psi, so that will put you at around 2700 - 2800 psi at the surface which is fine for most commercial concrete. Most the time run heater around 135 - 140 and that will take care of 95% of the grease. If really bad usually still don’t go above 165-170. And the PP unit will easily do that. Will tell you that anything over 150 you’re going to be sucking down diesel fuel like it was going out of style. Like 2+ gph. Measuring up my trailer tomorrow to see how big a tank I can get on it where I need to put it. The 8 gal tank doesn’t cut it for big jobs.


Thanks Maelstrom, that’s a good lead!

Maybe I should ask this question: is there anybody out there who is successfully cleaning greasy, oily, commercial concrete with an 8gpm, 3,000-3,500 psi system, similar to the Pressure-pro offerings we’re all familiar with? Maybe it doesn’t get as hot as other units, and maybe the psi/gpm specs truly are exaggerated… but in your experience, does it still get the job done?

Oh, just saw your reply. Thank you, this helps answer my last question.

Just remember a good degreaser is going to help do a lot of the heavy lifting.


Okay, I thought they both used the GX690
It is true the GX690 can’t provide 3500PSI at the 8gpm flow rate?
How can they advertise if not rated?

CETA, or someone like them, allows them plus or minus X amount of their ratings. Basically it’s false advertising in my opinion. Get the 690 and 8gpm and you will be around 3k. You can get 3500 wirh the 25ho kohler but I don’t think it’s worth the price difference. I want the new efi kohlers to be out a little longer before I go back to them.

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My sophomore year of college I had my first internship at Kohler Engines in Kohler, WI. I was the electrical intern for 8 months in the test lab. We ran endurance tests and torture tests on all the different models, including NVH (noise vibration and harshness) testing, cold room (indoor snow generator too), and heat rooms. It was really cool.

Kohler makes a quality product, we we ran comparison tests alongside Honda and Kawasaki and Subaru and Briggs. Kohler didn’t compare to Honda or Kawasaki small engines. Kohler has really great engines. Especially the commercial grades. But maybe Kohler is closer in performance to the higher ends brands now. This was in 2011, so who knows. But when they’d run engines until they exploded, Kawasakis and Hondas lasted longer.

Unrelated, they have an unbelievable kitchen and bathroom design center and their foundry is incredible.