This psi thing is kicking my brain.
Renting a Whirlaway 16" sc that apparently has a 225.025 (nozzle 25, deg 025) nozzles on it. All the other places rent MiTm 20" ones which I know are really too big.
Can either get a 3.7 gpm 3000 psi machine or a 4 gpm 4000psi machine.
I think I understand that the 4000 psi machine will now be about 2500 psi with those nozzles? or I might be totally wrong… brain is fried.
Doing a couple big residential driveways tomorrow, don’t want to throw down too many psi but want to have enough to get it clean with just the SC and no chems.
Appreciate the feedback…
and as a side note, I saw where you can see how many hours someone has been on the site… might not be accurate… I spend about an hour a day on this site from my work pc but am not logged in on it, nor is my cell phone logged in and I spend my lunches using it and reading on here, so it only tracks when I am on the tablet…lol… i might be scared to see how many hours I been on here over the last month plus… enough so that it is all a blur…
working on setting up my trailer this weekend… well starting it… can pick my 5.5 gpm 2500 psi tomorrow afternoon… buffer tank and hudson valve is on hand, just need to sort out all that plumbing needed… what to buy and how to connect it all… be burning this thing up all weekend…lol
Thanks, I think my post might not have been clear… lacking sleep for sure.
I am pressure washing the concrete driveways with a surface cleaner. I will not be doing any soft washing of the home or anything else… just surface cleaning with hopefully somewhere between 2000 and 2500 psi… just not sure with those nozzles if the 3000 psi or 4000 psi is the better option.
Yeah, it’s the flow you want to look at when calculating psi for a surface cleaner. As you already figured out, the 4gpm machine should push just a hair over 2500 psi through the 2.5 nozzles you have. 3.7 gpm would give you around 2200 psi.
So they’re both pretty close to each other. Just make sure the lower machine really is 3.7 and not 2.7 gpm. That happened to me once when I wasn’t able to rent the machine I usually had. Store employee told me they had a 3.5 and it turned out to be a 2.5
Some factors to maybe consider when picking up your rental today:
How much of a difference is there in rental cost?
Does one machine appear in better condition than the other?
How dirty is the concrete?
Oh, and congrats on your new machine! That’s exciting. Hit me up if you need any advice setting it up.
The PSI on a machine is the maximum PSI. So as long as it’s bigger than the PSI you want, they will be the same. Only difference in this case is a slight difference in the GPMs as @Infinity pointed out.
Went with the 4000 psi 4 gpm and was using a 16" whirl-a-way. Had to move real slow with it… so slow it made me a tad crazy. I definitely would rather move faster with smaller SC than slower with a bigger one… lord… but it did a great job… first homeowner was super duper happy and shocked at how bright his sidewalk, patio and driveway really were… didn’t even pre or post treat them…
2nd drive, patio and sidewalk - other side of the condo duplex also came out stellar… she won’t be home until Sunday to see it.
Got 3 requests for quotes while I was there… all 3 decks - been ages since I have done a deck…like years… and I never quoted the pricing, just did the work… so now I need to sort out how much to charge for deck work!
One lady also wanted a quote for a house wash for a 1.5 story vinyl house… some of the paint is oxidized, so I need to investigate that… no rest for this weekend but I am happy about it!
