So when you have 20 plus trucks anyone know the energy consumption differences?
Text me anytime for question 480-522-5227
Text me anytime for question 480-522-5227
5 GPM vs. 8 GPM
- Thread starter JDhomeservices
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Clean County PW
Active member
Interesting. Probably should be factored in there what your built to clean most. Handling multiple airports and college contracts I would think 8gpm pw trucks would be awesome.
Trae R
New member
This versus the cleaning speed increase of 8gpm measured would be nice to know.
810f250
Griffs Services PowerWash
Sounds like someone got a nice pump. 3200 is still good pressure for concrete cleaning.
Good questions, from a pure math theoretical perspective based on gpm, it would have a 60% increase in energy usage cost, and a 1.6 faster work speed.
But real world may be another story, just consider the initial cost of 8gpm vs 5 gpm and the repair parts cost also, the machine is heavier .... more transportation cost etc, what about fatigue, and worker liability issues from strains injuries
Questions to get you thinking of the big picture
Crud Cleaners
New member
I am interested on everyone's thoughts concerning Russ Johnson's Y. The Y being a Y shaped adapter with built in check valves to prevent back flow that splices two 4gpm machines into one hose. The end result is only an increase in gpm. So 2 gx390 4k psi/4gpm machines would produce 4000 psi at 8gpm. This is an all stainless steel device that he sells for right at 100 bucks. Seems like a pretty cheap upgrade for a cold water. Pros / Cons anybody?
Lee Rivenbark
www.ProPressureWashing.com (site in progress)
888-998-PROS
Changed the name but not here on this forum...not sure if original signature reads crud cleaners or not...
Lee Rivenbark
www.ProPressureWashing.com (site in progress)
888-998-PROS
Changed the name but not here on this forum...not sure if original signature reads crud cleaners or not...
apple
Moderator
Why don't you share?
apple
Moderator
I'm giving this a lot of thought lately. Our 8 gpm machines don't put out quite 3000 psi at the pump, so you know we're losing a lot by the time it gets to the end of the hose.
I've had it suggested to change pulleys to raise psi to 3600 and lower gpm to 6.8.
I'm interested in hearing anyones experiences on what to expect with the lower gpm.
I've had it suggested to change pulleys to raise psi to 3600 and lower gpm to 6.8.
I'm interested in hearing anyones experiences on what to expect with the lower gpm.
JDhomeservices
New member
Well, I rented on Alkota 4 GPM 4000 PSI hot water rig just to test out the difference between hot water in cold water. If they would have had a 5 GPM or 8 GPM, I would have tried one of those though. It ended up costing me about 20 dollars worth of gas and diesel to get this one driveway done. It took me about 6 hours. Now, granted, it was filthy and I had to wash it more than once to get all the swirl marks and stuff off after I had already washed and rinsed. I also had to take some extra effort to not let any wash water go down the storm drain right in front of his house. This rig with a 16 HP Vanguard and hot water did not seem to clean that much faster than my GX 390 pressure washer with no hot water though. It did seem to get it cleaner though. Maybe it's my fault for running a 20'' surface cleaner with only a 4 GPM
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cameronqueen
New member
End result looks good! Now go sell him a roof wash haha. I'm interested to hear what others say but my initial thought would be that a smaller surface cleaner would actually have made for quicker work with that flow...
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Guy Blackmon
Roundtable Host 2009
First off you should have pretreated the driveway with a roof mix, should of only taken about 1.5 hrs. But hey, its a learning experience.
We did this post construction project yesterday and took 8 hr. with 16 gpm. Glad I had the gpm
We did this post construction project yesterday and took 8 hr. with 16 gpm. Glad I had the gpm
We used a homemade one for a while before I knew that Russ had them.
Do it.
It won't double everything, but you will be impressed.
JDhomeservices
New member
I pre treated by downstreaming house wash mix. I guess that was not good enough.
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Guy Blackmon
Roundtable Host 2009
No not strong enough for that driveway, man that one is bad. When all else fails and you don't have a roof pump....get a pump up sprayer and apply that way. Work smarter not harder.
cameronqueen
New member
Don't mean to get off topic Guy, but when using a strong mix to pretreat a driveway like that how would you protect the grass that is right up against the concrete? Just careful application + a lot of pre-wetting the grass, or something more?
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Guy Blackmon
Roundtable Host 2009
No reason to, it may make the grass go dormant (on the edges) or in very few cases kill the edges it but who cares???...... That saves the customer from weed-eating for about a month, and it's what I tell them....No problem.
Oh I should also say that when treating concrete you don't have the run off or over spray of chems like in other applications, the concrete will absorb most of the mix. I can't ever remember having a problem with a 3-6% mix on concrete. Of course knowledge and experience play a large part in this.
Christopher
Moderator
Well, I rented on Alkota 4 GPM 4000 PSI hot water rig just to test out the difference between hot water in cold water. If they would have had a 5 GPM or 8 GPM, I would have tried one of those though. It ended up costing me about 20 dollars worth of gas and diesel to get this one driveway done. It took me about 6 hours. Now, granted, it was filthy and I had to wash it more than once to get all the swirl marks and stuff off after I had already washed and rinsed. I also had to take some extra effort to not let any wash water go down the storm drain right in front of his house. This rig with a 16 HP Vanguard and hot water did not seem to clean that much faster than my GX 390 pressure washer with no hot water though. It did seem to get it cleaner though. Maybe it's my fault for running a 20'' surface cleaner with only a 4 GPMmachine.
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With a 5.5 or 8gpm machine, that should have taken from 1-1.5 hours.
You will not work faster with a larger surface cleaner running only 4gpm, it does not work that way, a good rule of thumb is 4" of surface cleaner for every 1gpm, been there and done that with a 30" surface cleaner running only 5.6gpm, took forever and when I traded it in for the 24" surface cleaner, I did the same job the following month a lot faster.
I have found that sometimes those neglected driveways will not cleaner with pre-treating, some will but not all down here in the south, maybe it is the constant high humidity, salt air, salt water, hot all year long, etc... just don't know.
I have tried straight 10% and 12.5% pre-treating on some and it did not help any when there is embedded dirt in the concrete, bleach will not dissolve the dirt or turn it invisible like it does the mold, mildew and algae. One way to test what you are cleaning is put a few drops of bleach on the surface and watch it, if it changes you can bleach it, if there is no change, it is likely it is embedded dirt with the mold, mildew and algae and you have to get the dirt off mostly.
The hot water will help clean better almost all the time, sometimes more pressure will help if the concrete can handle it, a lot of concrete cannot handle a lot of pressure.
Christopher
Moderator
duplicate
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Christopher
Moderator
When adding machines together, you are only increasing the gpm's, not the pressure as the pump only puts out so many psi and gpm so when you add, you are only adding the gpm's.
I know several guys that use the adapter to connect a couple of the 4gpm machines to run the larger surface cleaners like the big guy, Steel Eagle 30", Mosmatic 30", etc..... and it works good for them. For most house washing you can have a guy washing the house and the other doing concrete and when done with the house, if there is a huge driveway you can just connect both machines together and run the large surface cleaner to finish faster. This can be done with larger gpm machines also, it really is a great idea.
Clean County PW
Active member
You do not want to lower the GPM if you can help it. Maybe chaining the pump out to a General pump TSF rated @8.5gpm @3500 psi or there abouts(I have to look for exact specs on that pump). You can find that pump with shipping around $700 but the cleaning capacity of it worth the expense big time.