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Default Power/pressure washers: GPM & PSI - are they accurate, what is moreimportant


I'm looking at a few gasoline-powered pressure washers.

Naturally, the typical specs a

a) the hp rating of the engine
b) the gpm
c) the psi

So my main question is - are these numbers fudged, or have a wide
accuracy range?

What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).
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Default Power/pressure washers: GPM & PSI - are they accurate, what is more important

In article , Some Guy wrote:

Your answer should not include "it depends on what you want to wash".


It depends on what you want to wash.
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Default Power/pressure washers: GPM & PSI - are they accurate, what is more important


I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


The second is 4 times better. Anything can give you pressure.
Even your grease gun can give you 10,000psi. The GPM rating
far outweighs the pressure rating.
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Default Power/pressure washers: GPM & PSI - are they accurate, whatis more important

Some Guy wrote:

I'm looking at a few gasoline-powered pressure washers.

Naturally, the typical specs a

a) the hp rating of the engine
b) the gpm
c) the psi

So my main question is - are these numbers fudged, or have a wide
accuracy range?

What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


IMHO -

If you focus the stream, the pressure indicates how intense that stream
will be. The GPM indicates how large an area you can clean per swath at
a particular pressure. So if your concern is cutting through tough
dirt in small areas, the pressure might be more interesting. If your
concern is covering large areas in a reasonable time, the GPM might be
what you want to look at.
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Default Power/pressure washers: GPM & PSI - are they accurate, what is more important

cjt wrote:

Some Guy wrote:


-snip-
Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


IMHO -

If you focus the stream, the pressure indicates how intense that stream
will be. The GPM indicates how large an area you can clean per swath at
a particular pressure. So if your concern is cutting through tough
dirt in small areas, the pressure might be more interesting. If your
concern is covering large areas in a reasonable time, the GPM might be
what you want to look at.



In other words. . . . "It depends on what you want to wash".g

Jim


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Default Power/pressure washers: GPM & PSI - are they accurate, what ismore important

On Jul 11, 9:25*pm, Some Guy wrote:
I'm looking at a few gasoline-powered pressure washers.

Naturally, the typical specs a

a) the hp rating of the engine
b) the gpm
c) the psi

So my main question is - are these numbers fudged, or have a wide
accuracy range?

What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


What are you washing
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Default Power/pressure washers: GPM & PSI - are they accurate, what is moreimportant

ransley wrote:

What is the minumum rating (in terms of gpm and /or psi) that
make it worth while to actually buy one of these things?


I think that is the more relavent question here.

What are you washing


Today it might be one thing.

Tommorrow it might be something else. Next year something completely
different.

Now do you see why asking "what do you want to wash" is irrelavent?

If I wanted to buy a set of wrenches, or a drill, would you be asking
"what want to assemble / disassemble?" or "what do you want to drill?".
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Default Power/pressure washers: GPM & PSI - are they accurate, what ismore important

Some Guy wrote:
ransley wrote:

What is the minumum rating (in terms of gpm and /or psi) that
make it worth while to actually buy one of these things?


I think that is the more relavent question here.

What are you washing


Today it might be one thing.

Tommorrow it might be something else. Next year something completely
different.

Now do you see why asking "what do you want to wash" is irrelavent?


If it was irrelevant why would you even need to ask?


If I wanted to buy a set of wrenches, or a drill, would you be asking
"what want to assemble / disassemble?" or "what do you want to drill?".




In the case of a drill are you hanging curtains or using it in your
steel erection business? Maybe a crappy harbor freight $9 drill will be
OK for the curtains.
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Default Power/pressure washers: GPM & PSI - are they accurate, what ismoreimportant

George wrote:

What is the minumum rating (in terms of gpm and /or psi) that
make it worth while to actually buy one of these things?

I think that is the more relavent question here.


Still not willing to answer that question eh?

Now do you see why asking "what do you want to wash" is
irrelavent?


If it was irrelevant why would you even need to ask?


Ask what?

I'm not the one asking "what do you want to wash?". I'm the one saying
"don't ask me that question".

How about this. I want to use it to wash my windows one day and carve
granite statuary another day. Does that help?

I'm asking if the GPM and PSI numbers (and engine HP numbers) can be
trusted from one make/model to the next.

I'm asking what are the minimum GPM, PSI and engine HP numbers that make
it worth while to buy and use these things.

If I wanted to buy a set of wrenches, or a drill, would you be
asking "what want to assemble / disassemble?" or "what do you
want to drill?".


In the case of a drill are you hanging curtains or using it in
your steel erection business?


Don't you think that if I had a "steel erection business" that I'd
probably have periodic contact with sales consultants for products that
you will never see in a Lowes or Home Depot and I would probably already
have several industrial-grade drills for us in my business?

Do you have to resort to that level of hyperbole to make an
inconsequential point?

If you have no actual experience owning / using a pressure washer, then
don't waste my time.
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Default Power/pressure washers: GPM & PSI - are they accurate, what is more important

On Sat, 11 Jul 2009 22:25:19 -0400, Some Guy wrote:


I'm looking at a few gasoline-powered pressure washers.

Naturally, the typical specs a

a) the hp rating of the engine
b) the gpm
c) the psi

So my main question is - are these numbers fudged, or have a wide
accuracy range?


Yes, expect a lot of fudging.


What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?


It depends greatly on the type of work and the quantity of it.

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".


Sorry but what you want to wash is a critical part of the
choice. A large sledge hammer is good for splitting logs, but it is
not very good at cutting diamonds.


I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


Depends. Some things clean up best with more volume and less
pressure and others with more pressure and less volume. In both cases
it generally is faster - better with more volume and pressure.


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Default Power/pressure washers: GPM & PSI - are they accurate, what ismore important

On Jul 11, 9:25*pm, Some Guy wrote:
I'm looking at a few gasoline-powered pressure washers.

Naturally, the typical specs a

a) the hp rating of the engine
b) the gpm
c) the psi

So my main question is - are these numbers fudged, or have a wide
accuracy range?

What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


From a homeowners useage point of view you will 'never' need more
than 2500psi, however you will often wish you had more than 2 GPM.
With 2500psi you can easily carve your initials in your wooden deck,
remove paint from your car, and blow window panes out of their
mountings.

KC
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Default Power/pressure washers: GPM & PSI - are they accurate, what ismore important

Some Guy wrote:

How about this. I want to use it to wash my windows one day and carve
granite statuary another day. Does that help?


You don't use a pressure washer to wash windows. You use a brush on a stick
and a hose or a bucket and a rag.

You might even consider a sponge and a squeegee.

I will leave the topic of window cleaning solutions for another discussion.

Jon



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Default Power/pressure washers: GPM & PSI - are they accurate, what ismore important

On Jul 12, 7:15*am, Some Guy wrote:
ransley wrote:
What is the minumum rating (in terms of gpm and /or psi) that
make it worth while to actually buy one of these things?


I think that is the more relavent question here.

What are you washing


Today it might be one thing.

Tommorrow it might be something else. *Next year something completely
different.

Now do you see why asking "what do you want to wash" is irrelavent?

If I wanted to buy a set of wrenches, or a drill, would you be asking
"what want to assemble / disassemble?" or "what do you want to drill?".


You dont get it, its all about what you wash, if its a 10ft side walk,
or a lawnmower its one need, if its a mud caked dump truck or a 500ft
building its another. Ive used the best units and the least powerfull,
sizing a tool is whats important like I dont use my 1/2 " hammer drill
to drill a 1/16" hole, but maybe you do. On that note id rather have
more gpm than pressure for my minimal needs
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Default Power/pressure washers: GPM & PSI - are they accurate, what is moreimportant


Some Guy wrote:

I'm looking at a few gasoline-powered pressure washers.

Naturally, the typical specs a

a) the hp rating of the engine
b) the gpm
c) the psi

So my main question is - are these numbers fudged, or have a wide
accuracy range?

What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


They are independent.

PSI = Cleaning power as it dictates the water velocity and thus cleaning
force.

GPM = Cleaning efficiency as it dictates the volume of high pressure
water and therefore the area that the cleaning force can be applied to.
The smaller the area, the longer it will take to clean a given surface
area, just like a 22" lawn mower vs. a 60".


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Default Power/pressure washers: GPM & PSI - are they accurate, whatis more important

Pete C. wrote:
Some Guy wrote:
I'm looking at a few gasoline-powered pressure washers.

Naturally, the typical specs a

a) the hp rating of the engine
b) the gpm
c) the psi

So my main question is - are these numbers fudged, or have a wide
accuracy range?

What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


They are independent.

PSI = Cleaning power as it dictates the water velocity and thus cleaning
force.

GPM = Cleaning efficiency as it dictates the volume of high pressure
water and therefore the area that the cleaning force can be applied to.
The smaller the area, the longer it will take to clean a given surface
area, just like a 22" lawn mower vs. a 60".


Well, that ain't exactly the whole story either...

The nozzle tip geometry has a great deal to do w/ the actual application
of the water to the surface and the effect thereon for whatever the
actual PSI/GPM ratings are...

--
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Default Power/pressure washers: GPM & PSI - are they accurate, what is more important


On Jul 11, 9:25 pm, Some Guy wrote:
I'm looking at a few gasoline-powered pressure washers.



What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


The numbers are real, but they are also somewhat meaningless other than
rough comparison. While you don't want to hear "it depends", in actual use,
it does. The rating figure is for the water coming out of the tip at close
range. In actual use, the 2000 psi unit held at a food or two is giving the
same pressure at the 4000 psi unit held a longer distance, and the object of
being cleaned in receiving far less than the rated numbers.

My experience is limited to a 2500 psi model and I've never wanted more,
either at home or at the shop. OTOH, if I wad dong heavy cleaning of power
plants every day, I'd go with bigger.


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Default Power/pressure washers: GPM & PSI - are they accurate, what is moreimportant

ransley wrote:

I've used the best units and the least powerfull, sizing a tool
is whats important like I dont use my 1/2 " hammer drill
to drill a 1/16" hole, but maybe you do. On that note id
rather have more gpm than pressure for my minimal needs


I can understand that if I'm washing something tough/nasty all day long
because it's my job, that I don't necessarily want the smallest nozzle
and spend a lot of time cleaning one spot because it's all my machine is
capable of.

There must be some minimum amount of PSI/GPM rating to make these things
worth buying for home or light commercial use.

And nobody has yet to comment on the power rating of the engine.

Since the engine is the real power behind these washers, how can it be
explained that there is such a wide range of power (from 5 hp to 15 hp)
yet the PSI and GPM numbers don't change very much, and sometimes two
different washers with identical GPM/PSI rating will have vastly
different engine HP rating.

I'm also looking at a sand pickup attachment (for wet sandblasting) that
claims to have a minimum requirement of 3 gpm @ 1500 psi.

http://www.princessauto.com/vmchk/sh...-sandblast-kit
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dpb wrote:

Pete C. wrote:
Some Guy wrote:
I'm looking at a few gasoline-powered pressure washers.

Naturally, the typical specs a

a) the hp rating of the engine
b) the gpm
c) the psi

So my main question is - are these numbers fudged, or have a wide
accuracy range?

What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


They are independent.

PSI = Cleaning power as it dictates the water velocity and thus cleaning
force.

GPM = Cleaning efficiency as it dictates the volume of high pressure
water and therefore the area that the cleaning force can be applied to.
The smaller the area, the longer it will take to clean a given surface
area, just like a 22" lawn mower vs. a 60".


Well, that ain't exactly the whole story either...

The nozzle tip geometry has a great deal to do w/ the actual application
of the water to the surface and the effect thereon for whatever the
actual PSI/GPM ratings are...


Yes, but most any given pressure washer can accept different nozzles,
the max PSI and GPM available to drive the nozzle don't change.
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Default Power/pressure washers: GPM & PSI - are they accurate, what is moreimportant


Ed Pawlowski wrote:

On Jul 11, 9:25 pm, Some Guy wrote:
I'm looking at a few gasoline-powered pressure washers.



What is the minumum rating (in terms of gpm and /or psi) that make it
worth while to actually buy one of these things?

The range I see are from 2 to 4 GPM, and roughly 2000 to 4000 psi.
Engine HP from 6 to 13.

Your answer should not include "it depends on what you want to wash".

I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


The numbers are real, but they are also somewhat meaningless other than
rough comparison. While you don't want to hear "it depends", in actual use,
it does. The rating figure is for the water coming out of the tip at close
range. In actual use, the 2000 psi unit held at a food or two is giving the
same pressure at the 4000 psi unit held a longer distance, and the object of
being cleaned in receiving far less than the rated numbers.


Pressure is in the hoses and lines up to the nozzle, there is no
pressure after the nozzle, only velocity.


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Default Power/pressure washers: GPM & PSI - are they accurate, what ismore important

On Jul 12, 10:47*am, Some Guy wrote:
ransley wrote:
I've used the best units and the least powerfull, sizing a tool
is whats important like I dont use my 1/2 " hammer drill
to drill a *1/16" hole, but maybe you do. On that note id
rather have more gpm than pressure for my minimal needs


I can understand that if I'm washing something tough/nasty all day long
because it's my job, that I don't necessarily want the smallest nozzle
and spend a lot of time cleaning one spot because it's all my machine is
capable of.

There must be some minimum amount of PSI/GPM rating to make these things
worth buying for home or light commercial use. *

And nobody has yet to comment on the power rating of the engine.

Since the engine is the real power behind these washers, how can it be
explained that there is such a wide range of power (from 5 hp to 15 hp)
yet the PSI and GPM numbers don't change very much, and sometimes two
different washers with identical GPM/PSI rating will have vastly
different engine HP rating.

I'm also looking at a sand pickup attachment (for wet sandblasting) that
claims to have a minimum requirement of 3 gpm @ 1500 psi.

http://www.princessauto.com/vmchk/sh...washer-accesso...


For light use my electric karcher is fine, its maybe 2 gpm at 1300
psi, a 13hp commercial unit may accept 6 gpm or more so it has the
extra power but my supplys are under 5gpm, sometimes 3gpm. Measure
your faucet gpm because buying more is a waste of money. For ocasional
use a 15 or 30a electric might be smarter, there are electrics that
use 3-5 gpm. Doing windows and carving granite are not what you get a
power washer for. So the questions of its use, are what determine what
is best, ive used the bigest Honda, I dont want one, it would be
overkill for me.
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"Pete C." wrote in message

Pressure is in the hoses and lines up to the nozzle, there is no
pressure after the nozzle, only velocity.


So when the water hits the surface, there is no pressure against it? You
can hold your hand against it and feel nothing?
Velocity is the rate of change of position, pressure is what you feel.


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Ed Pawlowski wrote:

"Pete C." wrote in message

Pressure is in the hoses and lines up to the nozzle, there is no
pressure after the nozzle, only velocity.


So when the water hits the surface, there is no pressure against it? You
can hold your hand against it and feel nothing?
Velocity is the rate of change of position, pressure is what you feel.


There is force from the mass of the water impacting the surface at a
high velocity, but this is not the same as the fluid pressure inside the
hose.
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"Pete C." wrote in message
ster.com...

Ed Pawlowski wrote:

"Pete C." wrote in message

Pressure is in the hoses and lines up to the nozzle, there is no
pressure after the nozzle, only velocity.


So when the water hits the surface, there is no pressure against it?
You
can hold your hand against it and feel nothing?
Velocity is the rate of change of position, pressure is what you feel.


There is force from the mass of the water impacting the surface at a
high velocity, but this is not the same as the fluid pressure inside the
hose.


True, but that force, or pressure is what counts, not the pressure inside
the hose. As you move the nozzle closer and farther from the target, the
force is going to change. Even though the figure is given in psi, the hole
in the nozzle is very small too, not an inch. Just as light falls off as
you move to increase the distance between the light source and target.


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On Sun, 12 Jul 2009 09:09:11 -0400, Some Guy wrote:

....

How about this. I want to use it to wash my windows one day and carve
granite statuary another day. Does that help?


I hope you are not planning to use the same tools for both.


I'm asking if the GPM and PSI numbers (and engine HP numbers) can be
trusted from one make/model to the next.


Not very. They both likely will have inflated their numbers.
This kind of misrepresentation is most common on consumer grade tools
than professional or industrial.


I'm asking what are the minimum GPM, PSI and engine HP numbers that make
it worth while to buy and use these things.


It depends on what you want to use it on. I would go a little
further and suggest that not only what you want to use it on but also
what make and model tool, not just the GPM and PSI.

Sort of like asking what the Towing capacity and the fuel tank
capacity is needed for for a car and not telling us what you want to
do with that car. We might guess you want to tow a boat, but that
could be a 40 foot power boat or a 10 foot row boat.

Would you tell you doctor you have a pain, and you want to
know what to do about it and refuse to tell him where the pain is, or
when you feel it?



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wrote:

I'm asking if the GPM and PSI numbers (and engine HP numbers)
can be trusted from one make/model to the next.


Not very. They both likely will have inflated their numbers.
This kind of misrepresentation is most common on consumer grade
tools than professional or industrial.


Can you cite any authoritative source that has done any sort of analysis
of several models of home, farm or light-commercial grade power washers
and has come to that conclusion or made that observation?

It's highly likely that what you say is true - just like the HP numbers
quoted for small gasoline engines have been in recent years. But I
would like to see something in print stating their observations or
measurements of these power washers.

Do you own or use any power washers?

I'm asking what are the minimum GPM, PSI and engine HP numbers
that make it worth while to buy and use these things.


It depends on what you want to use it on.


Would you buy a washer rated at 500 psi and 1 gpm? If not, why not?

Sort of like asking what the Towing capacity and the fuel tank
capacity is needed for for a car and not telling us what you
want to do with that car.


Even if I were to tell you, do you have the personal experience to know
how many GPM/PSI is needed to do task 1, task 2, task 3 and task 4? Are
you asking because if I tell you what task 1 is, you can tell me
authoritatively, specifically, how many gpm and PSI I need?

Would you tell you doctor you have a pain, and you want to
know what to do about it and refuse to tell him where the
pain is, or when you feel it?


Are you the doctor in this situation?

If I describe exactly what I want to clean, can YOU tell me the minimum
PSI and GPM I need?

Or do you just like answering a question with another question?
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Default Power/pressure washers: GPM & PSI - are they accurate, what ismore important

In article , Some Guy wrote:

Can you cite any authoritative source that has done any sort of analysis
of several models of home, farm or light-commercial grade power washers
and has come to that conclusion or made that observation?


My problem with your queries is that you're asking for a hell of a lot
more information than any one person is likely to have. Few people own
more than one pressure washer, or have owned more than a couple of them
in their lives. And almost none of them have ever verified the accuracy
of the stated GPM or HP.

I think the best you're going to get out of a bunch of random idiots
(and I mean that in a polite way) is anecdotal stuff such as:

"I used to own an ABC model 17 washer, with specs "such and such," and I
used it to do tasks X, Y, and Z. It was OK for X, fair for Y, and
useless for Z. Last year I bought a DEF model 99, with specs "this and
that," and it is more than I need for X, works well on Y, and is
acceptable but slow for Z."

If you get enough of those tales, you're going to have to tabulate and
analyze the results yourself. But I doubt you're going to get much
statistical significance out of a small group like a.h.r.

No one here is going to do a major research project for you, only
contribute small bits to your own research project. Maybe you can
approach CR, and tell them you'd like to write a piece on the topic, and
ask them for $20,000 to buy the washers, $10,000 to do the research, and
$10,000 to write the article.

Having said all that, I'd say spend the most you can afford on name
brand equipment, and limit yourself to tasks it will perform, as
determined by your own experience.

I know many here are happy with their units, but I've never seen the
need for a home owner quality, 120 VAC washer. I've got a very good
brass hose nozzle, no moving parts, and it's capable of doing everything
I need done. If I ever need something more serious done, I'll hire a guy
with a professional unit on a trailer, powered by an actual internal
combustion engine.
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Default Power/pressure washers: GPM & PSI - are they accurate, what is more important


I want to know if a washer that does 2 gpm @ 2000 psi has only half the
"cleaning power" as one that can do 4 gpm at 4000 psi (ie does the
cleaning power scale linearly with these numbers, or geometrically or
exponentially).


Another way of looking at these two washers is to make a more
common electrical comparison. This comparison difference will hold
true in pressure washers also.

2gpm @2000 psi would be represented by 2amps @2000 volts

4gpm @4000 psi would be represented by 4 amps @4000 volts

Power = Voltage x Amperage So........
The 2gpm washer equals 4000 units of cleaning power
The 4gpm washer equals 16000 units of cleaning power

* units of cleaning power undefined
* units of cleaning power are for reference/comparison only
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Default Power/pressure washers: GPM & PSI - are they accurate, what ismore important

On Mon, 13 Jul 2009 08:44:27 -0400, Some Guy wrote:

wrote:

I'm asking if the GPM and PSI numbers (and engine HP numbers)
can be trusted from one make/model to the next.


Not very. They both likely will have inflated their numbers.
This kind of misrepresentation is most common on consumer grade
tools than professional or industrial.


Can you cite any authoritative source that has done any sort of analysis
of several models of home, farm or light-commercial grade power washers
and has come to that conclusion or made that observation?
...


I have seen some test results, but nothing conclusive. I
would expect that the numbers are real and under the specific text
conditions, they are valid. The problem is each manufacturer, or even
different models may be measured using different methods.


Do you own or use any power washers?
...


Yes


If I describe exactly what I want to clean, can YOU tell me the minimum
PSI and GPM I need?


No. I would need to have more detailed information about the
equipment on the market, which I have never seen, and there would be
the difference in what I would consider minimum and what you would
consider minimum.

If time is no issue, then why use a power washer at all. a
standard hose will do the job. It may take weeks, but that 30 psi
will do it in time.



Or do you just like answering a question with another question?


I love answering questions with a question when the initial
question needs clarification.
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Default Power/pressure washers: GPM & PSI - are they accurate, whatismore important

I just aquired a 1800psi 2 gpm with a B&S 4.5HP. It will peal paint. I
was using a 1300 PSI electric that I thought was pretty good. For the
typical non-professional consumer (like me), the 1800/2GPM will do
most of what you want to do. If it is too powerful, hold the tip
farther fromt he surface to be cleaned. Also, there are an array of
tips that can be bought that will fit most jobs. Or, get an adjustable
one.

Hank ~~~keeping it simple

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