I currently have a 2.5 gpm/3100 psi machine that has thus far been reasonably good for soft washing houses. (Yeah, I know, but trust me, I make it work.) But where this machine is woefully inadequate is in the washing of driveways. It takes so long to do a driveway with the wand that I may as well not even bother. I have a 12 inch area washer but that’s just marginally faster than the wand alone. The washer also frequently slows down because it just doesn’t have enough preesure from the machine driving it. New nozzles on it would just be lipstick on a pig, since bottom line is that a 2.5 gpm machine just isn’t going to go fast enough to make doing driveways worth it. So I’m going to get a grownup 4 gpm machine. I’ve been told such a machine will offer the kind of professional power and speed I need. But before I pull the triggger, I need to ask a the stupid question: Is a 4 gpm machine going to be that much faster when doing driveways? Am I going to notice a real difference? Assuming appropriate nozzle size, what is the largest area washer I can use with a 4 gpm machine and still expect optimal speed and performance? And will a 4 gpm machine, with appropriate nozzles, drive my current 12 inch washer in a way that’s going to be a lot faster? Like I said, sorta dumb questions, but I have to ask them before I go out and drop $1k on a 4 gpm machine. Thanks!
I used to clean with 3000psi 2.5gpm machine with a CAT pump to do concrete. I didn’t know how to downstream back then using low pressure for house washing…I can’t see how it would have enough force to hit high peaks. I used it with a 20 inch Hammerhead to clean a few driveways. It worked but I had to walk slowly. It took forever to rinse. The average driveway took me about 2 hours.
Last year I bought a 4200psi/4gpm machine that was a world of difference in washing concrete. It cut my time in half just going up 1.5gpm. A 2.5gpm machine shouldn’t be used for anything in this profession. You can make a lot of money with 4gpm and work reasonably fast. I can easily run a 19 inch Whisper Wash Classic and do a driveway in less than an hour. Now I’m moving up to 5.5gpm which should cut my time in half again. Most of your time is spent rinsing which gallons per minute is king. Nozzle sizes will be 2502 to 25025 for a 4000/4gpm machine. The equation is 4 inches for every gpm your machine has so 4gpm can run a 16 inch surface cleaner efficiently.
Don’t drop a grand on a 4 gpm machine. Shoot for 5+ gpms. You don’t need 4000 psi for anything. You can get a good price on a 2500 psi 5.5 gpm machine. Alot of the guys here are running somewhere around 3000 psi including me. If you’re doing residential than 2500 psi will be plenty. Part of your problem, besides your undersized machine, is your surface cleaner. The more gpms you have the bigger the sc you can use and the faster you can move with it. Doing flat work with a wand is basically worthless as far as making money in a timely manner goes. Use the search bar. There’s quite a few threads where people have asked this same question, which is probably why no one has answered your questions.
Now I’m not saying that 4 gpms is no good. But I Can gaurantee that if you work with it for a few months you’ll wish you had something with more gpms. If that’s all you can afford then outs a first starting place but you might be able to save some $ and get 4gpms at 3000 psi and produce the same results.
