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Aaron Ochsner

Higher GPM PW's

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:p Hello all.....I am looking into purchasing a slew of new equipment for the upcoming season, and would like some advice, if you're willing. Most importantly I want to buy 2 new PW's....I have seen a model offered at highpowersupply.com which is 3500 psi@ 8 GPM. My focus with my work is wood restoration(this next season focusing on cedar roofs) , but I also will be embarking on flatwork/building pressure washing , and perhaps some fleet washing if it becomes opportune. My question is, do I need to have my own water supply tanks to use such a high water volume machine? Or can I expect a normal spigot to put this GPM out into the machine? Should I go with 5 GPM? Trailer Rig? Also for those of you who have experience with different GPM machines, what ? if any difference in efficiency did you find between a 5 GPM machine, and an 8 GPM machine? I want to note that I do at this point still need portable units, and I am mainly planning on buying cold water units, unless otherwise dictated by adverse response on this post. I know I have the artistry, and ability to perform professional work, but when it comes to equipment , I honestly am at a loss. I have never really been all that interested in the super-uber-technical data, but I do...of course want to purchase what is right for my operations :| Funny enough(don't laugh please) I really have no idea what upstream VS downstream is, and if anyone wants to help me that would be great. With chems, until this year on my own, I used garden pumps, and this year switched to a shurflo set up which I love. Again I am looking into purchasing 2 PW's this spring, and could really use the veterans advice with this.........Thanks so much in advance, and I hope your holiday season is filled with joy, and your belly filled with swedish glugg :)

Cheers,

Aaron

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It depends on what type a cleaning you’re doing. If you’re cleaning kitchen exhaust you want low volume. If you are cleaning houses then you are doing the right thing by going to high volume machine, it will cut your time in half. You will however need to tank feed the pump. I use a 225 gallon tank ( 500 gallon IMO. is too large and heavy and makes it more difficult to back the trailer.) with my setup and I have no problem keeping up with the 8.5 GPM. You should try leaving in the mornings with at least a 100 gallons in your tank incase your first job has a slow running spigot … make sure you feed hose going to your pump is at least ¾ in. I use a 1” with mine just to stay on the safe side.

You should also keep in mind that it is going to be a lot harder to heat the 8 GPM. verses 5 GPM. Becket make two burners, one that uses 2.5 gallons of fuel an hour and one that uses 5 gallons an hour, or something like that, I would have to get the manual out to be for sure. Anyways, you want the one that uses 5 GPH. You will also have to add about 80ft. of coil. and for that reason I recommend getting a lay down verses a vertical. The verticals are too top heavy. I ended up going with a regular size burner and just cutting my flow back by using a smaller tip size like 4.5, this way you keep your pressure @ 3500 PSI and the extra flow of water goes into bypass.

Keep in mind that 8 GPM @ 3500 PSI is going to be more physically demanding on you arms and shoulders…what I do most of the time is use a 20 size tip for most of my rinsing ( houses and flat work) and for decks I use a white # 10 tip and only run about ¾ throttle, this cuts your flow down to about 6 GPM and maybe 1800 PSI.

Upstream verses downstream…..upstream is pulling chemicals before the pump (high pressure) , and downstream is pulling chemicals after the pump ( low pressure). Personally I only use a downstream with my setup. If you’re going to use a downstream, there are things you need to know. First off make sure all your components are rated for 8 GPM., unloaded, gun, chemical injector. The key having a downstream chemical injector work properly is to have as little pressure at the injector itself, larger orifice sizes and shorter hose. I think this is why the x-jet works the way it does, there is no pressure at the injector but there is still water flow.

Sorry guys, I didn’t mean to write a book, I just got carried a way. I hope this helps.

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Guest rfitz

For what it is worth, I am switching from 5 GPM to 8 GPM, although I will try and only use a 100 gallon tank, but the city in which I live most houses pump out well over 5-6 gpm, if not more, I used a 55 gallon tank last year and it never got below 2/3 full, but rarely will you have your triggered pulled at a constant flow, and if it does start to drain your tank to fast, just switch tips to compensate, but for instance, if I am washing a house and it takes 2 hours,

only 60-70% of that time is your machine actually washing, the other time is running hoses, brushing, pulling chem lines,, etc.. my average time spent is 5 min per side applying soap and 10 min per side rinsing, as you can see, all your time is spent rinsing, also with wood work, all the manufactures highly reccomend going with lower pressure and higher volume, you get done twice as fast, with no damage being done to the wood, also with the heater, unless you are washing greasy or oily fast food drive thrus, you only want your heater to go up to a max of say 160-170 after that it actually weakens the strength of your soap if not destroy it all together, as far as being top heavy on the vertical heaters, I am mounting mine in the corner of my van, so that wont really be a factor, I guess it all depends on the individual set up,

as far as being phsically more demanding, I guess that is a push, if it is twice as hard to handle, but you finish in half the time, that just means you can wash twice as many decks or houses, etc.. in a day, my goal for 2004 is 2-3 decks a day, or 3-6 houses a day... We must have goals, without them, your are driving without a map..., Hope this helps

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Thank guys..........I have always appreciated your responses on the wood care board, and is by no means different. It will be a few months before I make any purchases, but listening to your posts, and perousing the board here at the grime scene has helped mucho..... Basically I see the issue as a bite the bullet situation, where as if I don't go for the higher GPM machines, I might as well become a SWB...... I do however wish to expand my efficiency , and I see investments in higer GPM machines to be just that .... I again, next season will be focusing on cedar roofs, as the sq ft'age makes a deck look like nothing. If I have to trolly around a 250 gal tank to make an 8 GPM move as it should........so be it....after 3 jobs it's all worth it.....However.......I have no intention on buying a hot water washer.....I am still not convinced I need it, nor does the majority of my work dictate it. Thanks again all :)

Aaron

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Using a smaller size tip is only applicable to pressure type unloaders, so if you plan on doing this with a machine, make sure that you do not get a flow type unloader.

Running the engine at 3/4's of full throttle can be a trouble maker. Not only is the flow going down, but the pressure as well. If the unit has a generator on it, it will not work correctly to provide enough juice for the burner, not to mention the charging system if it is electric start. The charging issue is even more important on a 12 volt unit, especially if it is a hot unit.

Best suggestion is to always run the engine at full rpm, and adjust pressure with different size tips. If you need to adjust flow, then I would suggest adding a valve to bypass water. This keeps the engine and pump running as they were designed to.

Also keep in mind that most of us are running air cooled engines, and anything less than full throttle can cause some problems there also.

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One tough pressure...... If you are running an 8 gpm pump and plan on cleaning decks, then you need to cut back on the gpm and the pressure as well, the only way I know of doing this is to cut back on the throttle….At this point you are not running the burner anyways and the charging system should not be affected by throttling back to ¾ throttle.....How would you add a valve to bypass extra water flow?

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Guest rfitz

I dont believe you have to throttle down your engine, if you just run lower tips thru your wand, you will get lower GPM's although I dont think it is great on your pump to do this everyday,..? I am running a 8 GPM new this week,

and have washed quite a few things with it, and have a 100 gallon tank, and that tank easily keeps up with my pump..

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Tom/Atlantic,

Smaller tips only apply to pressure type umloaders. Adding a valve on the high pressure side of the pump will allow you to bypass water and reduce flow. This is how Steam units work to super heat the water.

I have yet to add this to my unit, so can't give detailed instructions, but it can be done. One of these days I will add one so I can have true steam.

As far as reducing flow to clean decks, I have no clue there. I will have to trust you on that one.

Since I am in a warm climate area, I will not take the chance of running at 3/4 rpm. It may be possible to do it and never have any problems, but I am not willing to try it.

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Whatever you are comfortable with, that is all that matters, but I have never had a problem with the throttle except for when I was running my 12 volt burner, now I’m running propane so the charge is not as big a deal.

As for down sizing the tip, I know this will reduce the flow but you will be putting out the maximum pressure that your pump will allow. I want to reduce both flow and pressure. If I use a # 4 tip with my pump (8.5 GPM) I will get about 4 GPM at 3600psi..the extra flow goes into bypass.

Happy New Years to all.

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Atlantic,

Just a thought, could you put a reduced tip on a dual lance to drop the water flow, and bypass the extra pressure at the gun?

Although I must admit I'm confused, why buy an 8gpm unit, and then reduce flow?

Originally posted by Atlantic Power Washing

Whatever you are comfortable with, that is all that matters, but I have never had a problem with the throttle except for when I was running my 12 volt burner, now I’m running propane so the charge is as a big a deal.

As far down sizing the tip, I know this will reduce the flow but you will be putting out the maximum pressure that your pump will allow. I want to reduce both flow and pressure. If I use a # 4 tip with my pump (8.5 GPM) I will get about 4 GPM at 3600psi..the extra flow goes into bypass.

Happy New Years to all.

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Maybe I'm totally missing something, but varying the size of your tips will affect pressure NOT volume. If your pump puts out 8gpm at full throttle, it doesn't matter what size tip you're using, you're putting out 8gpm.... The ONLY way I know to reduce your gpm is to cut the throttle...which isn't good on the engine if it is air cooled.

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You're right, Mike. Don't know what I was thinking. Trying to think with the flu is probably a bad idea.

Still, looking at the thread above, what exactly is the reason someone would buy a 8gpm machine, and then reduce flow and pressure???

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If you reduce the tip size on a machine with a pressure type unloader, it will change the gpm, as the unloader will be bypassing water due to the smaller orifice tip. If you go with a bigger tip, then it will reduce pressure.

Now if you have a flow type unloader then you can not use smaller tips, as it will be to much back pressure and cause the unloader to stay in bypass.

Since I can not use smaller tips to reduce gpm with my flow unloader, I will be adding a bypass valve on the high pressure side of the pump to reduce the gpm. This will also enable me to have true steam, with very little runoff at all.

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Guest rfitz

Thanks Alan for explaining that for me, sometimes if you are on a low water

output job, smaller tips will get you thru in a pinch, I may of had 1 or 2 of those last year

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