10 GPM at 3000 PSI VS. 8 GPM at 3500 PSI

[Gunnerm1 14]

Hello.

Buying a new machine. Over the last 10 years I have plumbed two 4 at 4 machines together to get a grand total of 8 GPM at 4000 psi. Im tired of the issues associated with plumbing two machines together. Im debating on a 10 GPM at 3000 PSI VS. an 8 GPM at 3500 PSI.

This machine will be for flat work only, to clean your average residential type driveway.

I have a HydroTek hot water machine for gum and oil jobs.

What is your opinion?

[John T 744]

Hello.

Buying a new machine. Over the last 10 years I have plumbed two 4 at 4 machines together to get a grand total of 8 GPM at 4000 psi. Im tired of the issues associated with plumbing two machines together. Im debating on a 10 GPM at 3000 PSI VS. an 8 GPM at 3500 PSI.

This machine will be for flat work only, to clean your average residential type driveway.

I have a HydroTek hot water machine for gum and oil jobs.

What is your opinion?

I have similar to them on my flatbed. One setup is rated at 10.5 gpm at 3300 psi and the second one is 8gpm @3600 psi.. If yours is the numbers your saying I would go with the 8@3500 and I'll explain why.

If you have to run at times lets say 500' of hose expect to lose 500psi or thereabouts. So the 8gpm @3500 psi will still be around 3000 psi at the far end.. Large water Gpm is great but its good to have some kick on it when you need it. Also 8gpm is not to large where you can run most house water spigots into a water tank and use that PW and not run out of water. The 10.5 GPM could be twice the output of a house spigot.. And that could cause some more issues.

Good luck

[tonyshelton 112]

What issues have you had with plumbing the two together?

[Guy B 70]

I agree with John, 8 gpm is all we run you'll be fine with that. Plus running 10 gpm means you may have to jump up to 1/2 pressure hose & water issues as stated and you really don't want either.

[Gunnerm1 14]

I really appreciate the good advice. I was leaning toward the 8 GPM machine, and you guys just confirmed my thoughts on the subject. I will purchase the 8GPM.

As far as Tony’s question in regards to issues associated with plumbing two machines together. Plumbing two machines together has worked very well over the years, however, there are a few disadvantages.

When running two machines to run one surface cleaner you have twice the chance that a mechanical problem will shut you down. You need three jumpers hoses and two backflow preventers all of which can fail and have failed on me at some point in time.

There is just more moving parts, hoses, and connections to worry about. One machine will simplify the process a bit.

I’m just ready to have one machine do the job of two. I guess it is just a matter of preference.

But for anyone thinking of plumbing two machines together because that’s what they have to work with, go for it. You can take two relatively inexpensive machines, and clean the heck out of some concrete.

[tonyshelton 112]

I'm glad to hear you say that. We use two 5.5+ machines and sometimes we use them together and sometimes separate. We used to run one machine, but it costs too much money to call it a day when one goes down. Now we can limp along with the second machine if we have to in order to finish the days work.

[Christopher 102]

Something else to think about is pressure loss. With 8gpm running through a 3/8" pressure hose you will lose about 300psi for every 100' of hose.

When you go up to 1/2" pressure hose the loss is about 65psi.

When using 10gpm and 3/8" pressure hose the loss is about 350psi for every 100' of hose. If you use the 1/2" pressure hose the loss is about 100psi per 100'.

When I use my 8gpm machine I like to use my 1/2" hose as it does make a difference in cleaning with the surface cleaner as more pressure hits the surface instead of being lost due to internal hose resistance.

For house washing I just use the 3/8" hose since I am downstreaming and softwashing, I don't need pressure and with the 1540 or 0040 nozzles it is great flow for washing and rinsing up high.

Here is the Dultmeier pressure loss chart to take a look at: http://www.dultmeier.com/pdfs/tech-library/02Water8.pdf