Power washer principle
 

Does a power washer have to have pressurized water on the inlet, or will it
draw from a tank source?

Steve

Power washer principle
 

On Mon, 20 Sep 2010 07:32:29 -0700, "Steve B"
wrote:

Does a power washer have to have pressurized water on the inlet, or will it
draw from a tank source?

Steve


Most will draw from a tank, many older models do.

The big issue is making sure they get primed. Hence the tank needs to be
a bit higher than the pump.

Gunner


I am the Sword of my Family
and the Shield of my Nation.
If sent, I will crush everything you have built,
burn everything you love,
and kill every one of you.
(Hebrew quote)

Power washer principle
 

Gunner Asch wrote:

On Mon, 20 Sep 2010 07:32:29 -0700, "Steve B"
wrote:

Does a power washer have to have pressurized water on the inlet, or will it
draw from a tank source?

Steve


Most will draw from a tank, many older models do.

The big issue is making sure they get primed. Hence the tank needs to be
a bit higher than the pump.

A tank source higher than the pressure washer pump *is* a pressurized
source.

Most pressure washer pumps will not give you any reliable suction lift,
and can be damaged if they cavitate / run dry. As a general rule, if you
want to use water from a pond or the like, you will need to use a second
"charge" pump to get the water from the pond to the pressure washer. A
filter is also a good idea.

Power washer principle
 

On Mon, 20 Sep 2010 11:17:12 -0500, "Pete C."
wrote:


Gunner Asch wrote:

On Mon, 20 Sep 2010 07:32:29 -0700, "Steve B"
wrote:

Does a power washer have to have pressurized water on the inlet, or will it
draw from a tank source?

Steve


Most will draw from a tank, many older models do.

The big issue is making sure they get primed. Hence the tank needs to be
a bit higher than the pump.

A tank source higher than the pressure washer pump *is* a pressurized
source.

True but most folks dont consider .5psi to be "pressurized" but your
meaning is true indeed.

Most pressure washer pumps will not give you any reliable suction lift,
and can be damaged if they cavitate / run dry. As a general rule, if you
want to use water from a pond or the like, you will need to use a second
"charge" pump to get the water from the pond to the pressure washer. A
filter is also a good idea.


Very true.



I am the Sword of my Family
and the Shield of my Nation.
If sent, I will crush everything you have built,
burn everything you love,
and kill every one of you.
(Hebrew quote)

Power washer principle
 

On Mon, 20 Sep 2010 07:32:29 -0700, "Steve B"
wrote:

Does a power washer have to have pressurized water on the inlet, or will it
draw from a tank source?

Steve


My pressure washer has a little tank with a float valve that is filled
from from a garden hose supply. The washer draws water out of this
little tank. If i got a longer pickup tube i could just drop it in a
large tank of clean water.

Karl

Power washer principle
 

"Gunner Asch" wrote in message
...
On Mon, 20 Sep 2010 07:32:29 -0700, "Steve B"
wrote:

Does a power washer have to have pressurized water on the inlet, or will
it
draw from a tank source?

Steve


Most will draw from a tank, many older models do.

The big issue is making sure they get primed. Hence the tank needs to be
a bit higher than the pump.

Gunner

I have a 12v. ShurFlo RV pump that I use to move water around. Would that
help any at all?

Steve

Power washer principle
 

"Gunner Asch" wrote in message
...
On Mon, 20 Sep 2010 11:17:12 -0500, "Pete C."
wrote:


Gunner Asch wrote:

On Mon, 20 Sep 2010 07:32:29 -0700, "Steve B"
wrote:

Does a power washer have to have pressurized water on the inlet, or
will it
draw from a tank source?

Steve


Most will draw from a tank, many older models do.

The big issue is making sure they get primed. Hence the tank needs to be
a bit higher than the pump.

A tank source higher than the pressure washer pump *is* a pressurized
source.

True but most folks dont consider .5psi to be "pressurized" but your
meaning is true indeed.

Most pressure washer pumps will not give you any reliable suction lift,
and can be damaged if they cavitate / run dry. As a general rule, if you
want to use water from a pond or the like, you will need to use a second
"charge" pump to get the water from the pond to the pressure washer. A
filter is also a good idea.


Very true.

IIRC ...................

Salt water is .445 psi per foot of head.
Fresh water is .443 per foot of head.

1atm of air at sea level is 14.7 psi, not taking into account barometric
pressure variations.

At 33' of diving depth in salt water, it is 14.685 plus the 14.7, making it
very nearly 2 atmospheres, or 29.4 psi.

If you are using a gravity feed, the water source would have to be
57.11060948 feet higher than the power washer to provide 40 psig to the
washer, and that is allowing for the 14.7 psi for normal atmospheric
pressure.

So, it could actually be done with a water source about 60' higher than the
power washer.

I was just unsure if the power washer had any suction capabilities, or
needed a positive pressure feed. At those conversion factors, and allowing
14.7 psi for sea level pressure, it would take another 25.3 psi to just keep
up with it.

Or am I miscalculating, and it would take the full 40 psi?

Steve

Heart surgery pending?
Read up and prepare.
Learn how to care for a friend.
http://cabgbypasssurgery.com

Power washer principle
 

Gunner Asch wrote:
On Mon, 20 Sep 2010 11:17:12 -0500, "Pete C."
wrote:

Gunner Asch wrote:
On Mon, 20 Sep 2010 07:32:29 -0700, "Steve B"
wrote:

Does a power washer have to have pressurized water on the inlet, or will it
draw from a tank source?

Steve

Most will draw from a tank, many older models do.

The big issue is making sure they get primed. Hence the tank needs to be
a bit higher than the pump.
A tank source higher than the pressure washer pump *is* a pressurized
source.

True but most folks dont consider .5psi to be "pressurized" but your
meaning is true indeed.
Most pressure washer pumps will not give you any reliable suction lift,
and can be damaged if they cavitate / run dry. As a general rule, if you
want to use water from a pond or the like, you will need to use a second
"charge" pump to get the water from the pond to the pressure washer. A
filter is also a good idea.


Very true.



We've used a cheapie bulge pump and car battery to provide


We've used a cheapie bulge pump and car battery to provide lake water to the
pressure washer.

But the washer won't pull water up very far by itself...
--

Richard Lamb

Power washer principle
 

On Mon, 20 Sep 2010 22:03:02 -0700, "Steve B"
wrote:


"Gunner Asch" wrote in message
.. .
On Mon, 20 Sep 2010 11:17:12 -0500, "Pete C."
wrote:


Gunner Asch wrote:

On Mon, 20 Sep 2010 07:32:29 -0700, "Steve B"
wrote:

Does a power washer have to have pressurized water on the inlet, or
will it
draw from a tank source?

Steve


Most will draw from a tank, many older models do.

The big issue is making sure they get primed. Hence the tank needs to be
a bit higher than the pump.

A tank source higher than the pressure washer pump *is* a pressurized
source.

True but most folks dont consider .5psi to be "pressurized" but your
meaning is true indeed.

Most pressure washer pumps will not give you any reliable suction lift,
and can be damaged if they cavitate / run dry. As a general rule, if you
want to use water from a pond or the like, you will need to use a second
"charge" pump to get the water from the pond to the pressure washer. A
filter is also a good idea.


Very true.

IIRC ...................

Salt water is .445 psi per foot of head.
Fresh water is .443 per foot of head.

1atm of air at sea level is 14.7 psi, not taking into account barometric
pressure variations.

At 33' of diving depth in salt water, it is 14.685 plus the 14.7, making it
very nearly 2 atmospheres, or 29.4 psi.

If you are using a gravity feed, the water source would have to be
57.11060948 feet higher than the power washer to provide 40 psig to the
washer, and that is allowing for the 14.7 psi for normal atmospheric
pressure.

So, it could actually be done with a water source about 60' higher than the
power washer.

I was just unsure if the power washer had any suction capabilities, or
needed a positive pressure feed. At those conversion factors, and allowing
14.7 psi for sea level pressure, it would take another 25.3 psi to just keep
up with it.

Or am I miscalculating, and it would take the full 40 psi?

Steve

It simply needs to have water available for the suction side to be able
to pick up. Like from a tank mounted next to and feeding the pump.

Its not rocket science..its simply a pump that has some suction. GPM on
the average high pressure pump is quite low, hence they really dont need
a lot of water to spray properly.




Heart surgery pending?
Read up and prepare.
Learn how to care for a friend.
http://cabgbypasssurgery.com



I am the Sword of my Family
and the Shield of my Nation.
If sent, I will crush everything you have built,
burn everything you love,
and kill every one of you.
(Hebrew quote)

Power washer principle
 

Maybe, but it is dangerous for the high pressure pump. It is a general rule of thumb that ALL high pressure pumps be fed by a low
pressure supply slightly greater in volume than the max capacity of the high pressure pump to prevent damaging cavitations at the
high pressure pump inlet.
Steve

"Steve B" wrote in message ...
Does a power washer have to have pressurized water on the inlet, or will it draw from a tank source?

Steve

Power washer principle
 

On Tue, 21 Sep 2010 01:24:11 -0700, Gunner Asch
wrote:


It simply needs to have water available for the suction side to be able
to pick up. Like from a tank mounted next to and feeding the pump.

Its not rocket science..its simply a pump that has some suction. GPM on
the average high pressure pump is quite low, hence

As is so often the case, you don't have a clue. Some pressure washers
such as the CAT models that used an intake tank should be OK with
modest suction lift. But most modern consumer-grade models probably
aren't. Both of mine will fail to leave unloaded-mode if the pressure
intake is restricted very much. Which is probably one of the reasons
that most owner's manuals I've seen specifically warn against going
below about 20 psi on the intake side. But what do they know compared
to the Taft oracle?

they really dont need a lot of water to spray properly.

Oh really? One of mine is the popular 13hp 4.5 gpm types. Why don't
you show us how to calculate the suction specs for that?

Ever thought of not commenting when you when you haven't anything
useful to say? Of course not.

Wayne

Power washer principle
 

What's that Lassie? You say that Steve B fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Mon, 20 Sep 2010 22:03:02 -0700:

If you are using a gravity feed, the water source would have to be
57.11060948 feet higher than the power washer to provide 40 psig to the
washer, and that is allowing for the 14.7 psi for normal atmospheric
pressure.

Do you need 40psi? Is that what the pump mfg. says, or is that what
you have from the garden hose?

I would think that as long as you don't suck air, or cavitate, you
could be at 0 psi.
--

Dan H.
northshore MA.