# Pressure Washer question



## kingsebi

Currently using a 2800 psi 3 gpm pressure washer with a cat pump. Mostly paint but do a fair amount of pressure washing. Mainly houses, decks, driveways etc. Will be upgrading soon. Will be keeping my old unit for small jobs but want a bigger unit to increase efficiency.

All the models I'm looking at are Pressure Pros belt drive.

4000psi, 4 gpm, General pump
4000psi, 4 gpm, Cat pump
3000 psi, 4.5 gmp Cat pump
3500 psi, 5.5 gmp, General pump

Is the last one listed (5.5 gmp overkill? Is it worth the almost $3k?
Will be using a buffer tank so no problems on water supply. Let me know what you think. Any opinions are welcomed. 

What do you think Ken?


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## Dave Mac

Ken is gonna say gpm is king get a 8gpm, but 5.5 is the best you listed, general pumps are easier to get parts and easier to work on Im just guessing here:whistling2:,


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## kingsebi

Thats funny. I've been reading these things for years and you are right. I think thats what he'll say too. But it's all about cost and what's the most I will need. No reason to spend money unnecessarily. But don't want to go too small either.

Curious between 4000/4gpm & 3000/4.5gpm? which one cleans better? Which will be easier to use?


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## Ace Painting

The 5.5 is good 8 is better. If you go with 8 gpm you will probably need a buffer tank, which will take up room and complicate things a bit. The 5.5 should be good if you have good water pressure by just hooking up to the hose.


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## PressurePros

Dave Mac said:


> Ken is gonna say gpm is king get a 8gpm, but 5.5 is the best you listed, general pumps are easier to get parts and easier to work on Im just guessing here:whistling2:,


Everything Dave said :thumbup:

If you are looking to really up the ante on efficiency and are willing to go to $2,700 for a 5.6 gpm, spend the $3,000 and get the 8 gpm. You'll never look back.


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## kingsebi

*Thanks*

Thanks Guys


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## Tonyg

I have the 3500 psi, General pump. Works great but I would love to have the 8gpm. If you're running a crew I wouldn't hesitate to go with a 10gpm to run 2 guns. 

When I bought mine I had planned on the 4gpm but I wanted to get more than I would need so I would have enough. Now, when I do replace my current rig I will buy the 8gpm for sure. Flow, cleaning power, speed, efficiency - all require the 5.6 or higher


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## the paintman

PressurePros said:


> Everything Dave said :thumbup:
> 
> If you are looking to really up the ante on efficiency and are willing to go to $2,700 for a 5.6 gpm, spend the $3,000 and get the 8 gpm. You'll never look back.


 Lets be clear just in case someone takes this advice out of context and regrets it later. And I am only asking because i don't know for sure and in 30 years in this business i have never owned anything larger than 5gpm. 
I currently have about 8 pressure washers. Two are trailer mounted rigs with 100 gal tanks and the rest portable.

Now this is the question. You will never run those 8.5 gal rigs of of normal city water will you?
And they also will suck 100 gallons out of a tank way faster than the city water can supply it especially if two men are working off of it. Thereby stopping production and efficiency and the two men taking a long extended frinkin cell phone break. I have had that happen with my small pumps on certain occasions when the water supply sucked and could not keep up. (It sounds a little bit like a repeat of the tortoise and hare story here. Just saying...)

Don't get me wrong I'm not saying those pumps arent great and that i wouldn't want 1. In fact I could see them being a huge plus on whole subdivision walkeways and drives where we are using surface cleaners. For these jobs do you run off the Fire Hydrant? So that begs two final questions. When 2 people are running off 1 pump. Does one pump draw all the available water when the other gun is off? And will two surface cleaners run efficiently off 1 machine efficiently? 

TIA


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## 1camper

Those are good points. Yes, unless a machine is equipped with two unloaders when one is not in use all the water goes to the other open gun. Running two flat surface cleaners that might not be a big deal, up in the air trying to maintain balance, it's a different story.

One other point about 8gpm.. The largest nozzle commonly carried by retailers is #8, most guns will only allow 8gpm to flow thru them, also many unloaders top out at 8 gpm. This means if you're using a 3,500 psi @ 8 gpm, you lose the flexibility of using a larger nozzle size for less pressure.. even if you put a #10 on, all your gun and unloader will allow thru it is 8gpm. All you can do to cut the pressure down is take away water and in turn lose efficiency. ...or just wash houses with chemical tips.  

Most all pressure washers are sold with a collection of tips that will achieve the maximum psi of that machine. It's up to you to tailor the machine for your purposes or just have one built for your purposes. I favor two machines over one and a minimum of 5.5gpm, pressure is relative to the work being done. Essentially a low pressure and a high pressure machine. The low pressure has more flexibility and is used for more surfaces, the high pressure is used to operate a flat surface cleaner primarily.


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## PressurePros

You do have to be conscious of your supply. If you are in a rural area with well water you would need a larger supply tank. no matter what size your machine is, you should have a reserve/supply tank so that you can plumb your unloader back into it. This keeps your pump circulated with cool water and prevents cavitation caused by inadequate supply. I run 10 gpm machines with no problems on twin 55 gallon supply tanks. 

My tens were set up with dual lines (one unloader). I quickly switched back to using one line. The rinsing power of ten gpm is incredible and was faster than running two lines at under 5 gpm each. And yes, even with undersized downstream injectors left in-line to balance flow, there were still issues. if you are going to run two lines, you need two pumps.


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## 1camper

Curious, how much pressure do you run with a 10 gpm machine? Seems like that much water, under pressure, would wear you out unless you use it for flat surfaces..


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## PressurePros

1200 psi is the max output of the pump. Generally we use between 800-1000 psi for everything. Commercial concrete is the only time higher pressure and hot water are used.


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## 1camper

I guess my first observation would be 110 gal / 10 gpm is only 11 min trigger time. You can refill constantly at around 6.5 or 7 still seems like a lot of wait to fill time or a short workday... Secondly, how do you get the wasps nest stems off with only 1000 psi ? 


The old formula for comparing pressure washers is psi*gpm equals "cleaning units" . So 10 gpm * 1000 is very similar to 5.5 gpm * 2000. There is a weight of water factor imho. I'm not sure the physics exactly but I'm sure 2.5 gpm @ 4000 is not equal to 5 @ 2000. I'd rather have more water any day and easier to use as well.

I saw a couple of links you posted for an 8 gpm machine but didn't see the 10 at pressure tek. If you don't mind post a link I'd like to see it, thanks!


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## Ultimate

1camper, 

I see your online right now so here is a link for a good read if nothing else. 

http://www.ptstate.com/index.php/topic,3966.msg51134.html#msg51134


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## 1camper

Ok, I see the pics but don't see the actual product listed anywhere on his site. It's direct drive??


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## PressurePros

1camper said:


> I guess my first observation would be 110 gal / 10 gpm is only 11 min trigger time. You can refill constantly at around 6.5 or 7 still seems like a lot of wait to fill time or a short workday... Secondly, how do you get the wasps nest stems off with only 1000 psi ?
> 
> 
> The old formula for comparing pressure washers is psi*gpm equals "cleaning units" . So 10 gpm * 1000 is very similar to 5.5 gpm * 2000. There is a weight of water factor imho. I'm not sure the physics exactly but I'm sure 2.5 gpm @ 4000 is not equal to 5 @ 2000. I'd rather have more water any day and easier to use as well.
> 
> I saw a couple of links you posted for an 8 gpm machine but didn't see the 10 at pressure tek. If you don't mind post a link I'd like to see it, thanks!


The 10 gpm was a custom build Pressure Tek was offering. I don't think Bob is building them anymore (maybe if I ask him nicely).

My cleaning is done with landscape and home friendly cleaners via downstream injection. The chems melt the insect nests and a 0 degree tip applies plenty of pressure to knock them down. Using cleaners is all about rinse speed. That is where the 8-10 gpm blows lesser machines away. Also keep in mind that trigger time is never 100%. 

Here is a pic of one of my guys using a zero degree. That stream can hit 40' and still have enough ooomph to knock down a nest.


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## 1camper

Different strokes.. I'd suggest you're losing something in transfer efficiency that I'm not. I use 5.5 - 6 gpm and have 100% trigger pull time, only a small bladder tank. This isn't a good picture cause I had to take it myself, lol. That's a 16' pole in my left hand, phone in my right. I wet them down with chemical, go over them @ 8" and 25* all the way to the ground then rinse them clear with clear water and a 15* chemical tip. From a 10' step, I can clean to 35' and 25' wide. I do a vinyl sided two story on a slab in less than two hours. There is a sea of them here...lol. If I lived where there are hills I'd have to do something different!

http://


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## Sirocco Jerry

Good thread guys,
but I also see a couple perspectives in question..

how much flow can a man manage ?
I'm told a 200lb man can move as fast as a 6.5gpm washer can flow,
250lb ex-linebacker.. give him 8gpm, and a bonus program.
IF you're in southern Cali, and all yer help is 150 to 170lbs..
4 to 4.5gpm is all you can expect out of those guys for workspeed.
..now don't anyone get offended here..
the Owner of a company cleaning is a completely different endurance level than a workerbee..
so if you weigh 160 and you toss a 8gpm wand around like a pro wrestler, 
..that's called determination.. AKA.. "gettin'the job DONE". Eh?

Now about pressure..
IF flow was all you needed, we wouldn't be building pressure washers at all.. 
we'd be pushing hydrant meters.
If you throw water at a house at 275mph (3000psi)..
you are "rinsing" at 3 feet away, and blasting at up to 12" away.
throwing water at 400mph (4000psi) you can stand back farther, take bigger passes, and cover more area faster, with the same flow (GPM).
..Don't diminish the "quality of clean" ..AKA.. pressure,
for faster "coverage" without "affecting the surface.
Looking like you're cleaning isn't the point.
..and Chemical salesmen love to push bigger machines, so..
remember..
the jobsite tells YOU what it needs..
Consider coverage AKA.. gpm ..AKA.. WorkSpeed,
Consider Quality of Clean, AKA.. psi *at the surface*
Consider water supply, (dryer states don't want to see a "fire-hose" blowing everywhere on a hot dry day,)
Consider the user, and whether he can feel successful at the end of every day without feeling like he got his A$$ kicked..
..Because he might just quit on the 2nd day of a week long job.
I call this sustainability in the crew.

One more thimg..
*distance..*
IF you try jo jam 8gpm down a 3.8" hose that is 300ft long,
..and you styart with 3000 psi..
you'll only have about 2200psi at the wand
the same 23hp engine can push 6.5gpm at 4000 psi trough 300 ft and still have 3400psi..
..so remember the Jobsite.. and *clean it effectively*

I'm just tryin 2 help.


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## Tonyg

I once had a mechanic at a pressure washer repair shop tell me that you can't reduce the pressure without adjusting the unloader. 

I was at SW one day and mentioned to the staff what I was doing to a deck. I was amazed by his expert comment that you can't strip a deck - "that's why they call it stain"

No offense, but it doesn't take an NFL linebacker to hold a hose. I wash a house with less than 200psi and using 3000psi will not clean better. Normally, a horizontal hose will not lose significant pressure (chem draw yes) and 300ft is normal for me. 

I have to disagree with your assessment


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## PressurePros

We rarely go over 1000 psi for anything. Very manageable and very fast with high flow. The chems do the work. I love competing against guys that use those noodle wands and pressure. Level of cleanliness and speed with the right cleaners and high flow rinse blow away the old-school methods. I know many guys don't want to hear that but it is what it is. I have done both ways. 

Did I mention I love non-pressure washing?


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## 1camper

"noodle wands" would indicate some floppy out of control attempt at pressure cleaning. That's what I love, pressure cleaning. What happened to my pic BTW?


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## 1camper

*Tonyg - No offense, but it doesn't take an NFL linebacker to hold a hose. I wash a house with less than 200psi and using 3000psi will not clean better. Normally, a horizontal hose will not lose significant pressure (chem draw yes) and 300ft is normal for me. *

Sure, I can clean a house with a hose and a brush, some chemical. Might have to scrape some flaking paint and some muddobber nest. How long will it take? Drudgery may be honorable but its not profitable. I can clean circles around any guy with a hose.


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## Sirocco Jerry

There's more than 1 way to clean..
"pressure" cleaning,
Chemical cleaning with "SoftWash" rinse,
..and the bucket n brush method.

no argument here,
but since I teach environmental cleaning..
I recommend methods that minimize the use of chemical.


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## Tonyg

1camper said:


> *Tonyg - No offense, but it doesn't take an NFL linebacker to hold a hose. I wash a house with less than 200psi and using 3000psi will not clean better. Normally, a horizontal hose will not lose significant pressure (chem draw yes) and 300ft is normal for me. *
> 
> Sure, I can clean a house with a hose and a brush, some chemical. Might have to scrape some flaking paint and some muddobber nest. How long will it take? Drudgery may be honorable but its not profitable. I can clean circles around any guy with a hose.



Dude, you must have misunderstood the post. I was referring to a 3/8 pressure line from Sirocco's post. Read slower and click carefully before you start doing your circles. Last Friday I did a house wash on a 2200sf 2 story in suburbia, cleaned the driveway, and did a light strip for a maintenance stain on a small 300sf deck. The house was washed with <100psi in 1 hour 15min, the deck cleaned in 30min with 700psi, and the driveway cleaned in 30min with 3500psi. I didn't need step ladders or extension poles and it was profitable.


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## PressurePros

I've known Tony for awhile and his techniques nad efficiency are similar to mine. This is the way pros wash in 2013. I'm not knocking your technique, its just not done your way much. Definitely more than one way to skin a cat as Jerry mentioned. 

I'm sure Tony will say the same thing.. I will put a chem wash up against a pressure wash and win every day of the week. Pressure doesn't clean as well.


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## 1camper

Bring it. 

You said you use 1000 psi @ 10 gpm, he said he uses less than 100 psi... Which is it?

There's nothing new about sodium hypochorite or service.


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## PressurePros

House washing is nozzled for 800 psi. What actually hits the house I have no idea. Its low, but above garden hose pressure. Like I said, whatever works for you is the best method.


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## Ultimate

http://www.google.com/url?sa=t&rct=...=RKqylB71xp_7zGIGhCI34A&bvm=bv.44158598,d.eWU

http://www.asphaltroofing.org/sites/default/files/tech-bulletin/tb_217.pdf

http://www.google.com/url?sa=t&rct=...Rwxe8dWzhARv2owHQ&sig2=Pwf-YNpGOfKThBi8LCti-w

I can't find one manufacturer of nearly any exterior composite, including paint, used for architectural construction that recommends high pressure for cleaning. Except concrete and even then things should be dialed in.


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## Tonyg

Here is a chart that I use that may be helpful. If you are using a 15* chem/soap tip, you are using a 1540. As far as a 10gpm in comparison to a 5gpm, umm... that would mean double gpm, I could be wrong, and would be sure to function differently. I would have already bought the 8gpm if I didn't need more horse power.


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## Ultimate

Tonyg said:


> Here is a chart that I use that may be helpful. If you are using a 15* chem/soap tip, you are using a 1540. As far as a 10gpm in comparison to a 5gpm, umm... that would mean double gpm, I could be wrong, and would be sure to function differently. I would have already bought the 8gpm if I didn't need more horse power.



Printing that out now.


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## Tonyg

HouseOfColor said:


> Printing that out now.


If you're not using a 5.5 gpm / 3500 the numbers won't work for you. What are you using?


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## Ultimate

4 gpm 4kpsi  

I realized that if you have one specific to my specs all the better I'll print it out too. The specs will be changed with a new pump before the end of April. More like 8gpm with 2000 psi max.


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## Tonyg

HouseOfColor said:


> 4 gpm 4kpsi
> 
> I realized that if you have one specific to my specs all the better I'll print it out too. The specs will be changed with a new pump before the end of April. More like 8gpm with 2000 psi max.


8gpm with 2000psi? Wouldn't that be more like 3k?


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## Ultimate

Not sure exactly Tony. I should have been more specific. 

Right now I have a Honda gx630 pushing a little cat pump giving me 4 gpm and 4000 psi max. 

http://www.northerntool.com/shop/tools/product_200317423_200317423

A local outfit is telling me the Honda has enough for a General or Comet pump with a direct drive gear reducer to get me 8 gpm in the neighborhood of 2000 psi. I'll be talking with Bob about it too when I get around to it. We didn't get to specific with the psi I am more interested in the flow. I'm going with gear rather than belt just because of the layout of my trailer. Not much room for a belt drive and I want to wait until winter of 2014 to set up on a new trailer.


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## PressurePros

This will work better for you, John.


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## Ultimate

What are the numbers in black representing Ken?


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## Ultimate

Tonyg said:


> 8gpm with 2000psi? Wouldn't that be more like 3k?


So I'm rinsing with 0030 high and far and 2540 down low on windows and screens and such on this 4gpm. According to this graph if I am reading it right I am hitting the house with < or = 40 psi....

If so I love it. It's effective no doubt as much as possible @4gpm. It's good to know the exact number when selling jobs too.


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## PressurePros

HouseOfColor said:


> What are the numbers in black representing Ken?



Nozzle orifice. 

A #20 on 4 gpm is somewhere around 350 psi.


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## Ultimate

PressurePros said:


> Nozzle orifice.
> 
> A #20 on 4 gpm is somewhere around 350 psi.



Got it thanks. 

The 0030 is getting me every bit of 35' on a pistol grip and likely 40' on a non windy day with wand on it. Plenty of umph to knock down bees nests after hitting them with soap first. 

The 2540 is great on everything 10' and lower. Especially windows and screened porches. 

I know your graph doesn't give a psi for what I am using but it must be very low which is great for me as well as everything rinses considering I have only 4gpm. 

The graph Tony posted is accurate? Maybe I am not reading it right but according to his, a #20 gives me 160 psi. 

I don't have a gauge I can place after the tip to measure. It's really not that important I suppose just curious and would like to be able to spew off a real number when doing face to face estimates.


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## PressurePros

I didn't even notice Tony's chart for the 4 gpm. I did the calculation in my head and must have been off on my math.


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## Ultimate

Ken you never make mistakes! 

Thanks for the chart mister. The cold stopped me here for a few days too just when things were beginning to get rolling.


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## PressurePros

I haven't been sick in 7 years but I think I am getting it now too. Great timing huh? Of course, I put off estimates Thursday and Friday and now have a full day tomorrow.


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## 1camper

The easy way to remember the nozzle chart is the nozzles correspond to how much water will pass thru at 4000 psi. At 4000, the number of the nozzle is equal to the gpm. As I recalled the old formula psi*gpm equals "cleaning units" .... So Ken using 10 gpm @ 1000 is comparable in "cleaning units" to me using 6 @ 2000. If you are using less than 100 psi you would have to be moving about 100 gpm...which you're not.

A garden hose/ supply line will knock down a wasp nest, no problem. It's the stem that's difficult to remove..unless you just paint over them, lol.


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## Ace Painting

camper, I don't think cleaning uits would be involved because the chems are doing the majority of the cleaning and the pressure washer is there basically for rinsing. Great thread, can't wait for spring to get out and make some money.


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## Sirocco Jerry

Higher pressure with adjustability allows for more multifunctionallity..
example: 
Coatings removal, and surface prep has some of my friends working all through winter..
Indoor blasting.. warehouses, distribution centers, etc.

Pollution happens.. and it needs to be cleaned up..
Once the surface is prepped.. coatings become opportunity again.

The more you know about new tools, the more you will find profitable work
indoors or out.

..and this is stuff your competition does NOT want you to think about.


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## Ultimate

Sirocco Jerry said:


> Higher pressure with adjustability allows for more multifunctionallity..
> example:
> Coatings removal, and surface prep has some of my friends working all through winter..
> Indoor blasting.. warehouses, distribution centers, etc.
> 
> Pollution happens.. and it needs to be cleaned up..
> Once the surface is prepped.. coatings become opportunity again.
> 
> The more you know about new tools, the more you will find profitable work
> indoors or out.
> 
> ..and this is stuff your competition does NOT want you to think about.


Good thing to think about Jerry. Seems like starting about now, a bees nest has been poked and pressure washers are all over, a few months later they've disappeared again. I'd like to do the numbers and other research with reclamation. For future ideas.


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