Reduced pressure

L

Lenny Schrecengost

New member
I recently read a post about using a 1/2 hose because the pwer was loosing pressure when he went to 7 or 8 gpm. I can not find it. I think it was on this board or the UAMCC. Can anyone help me find it. We are getting ready to get a larger trailer and put 2 machines together to get the volumn and I want it to work as good as possable.
 
Lenny Schrecengost said:
I recently read a post about using a 1/2 hose because the pwer was loosing pressure when he went to 7 or 8 gpm. I can not find it. I think it was on this board or the UAMCC. Can anyone help me find it. We are getting ready to get a larger trailer and put 2 machines together to get the volumn and I want it to work as good as possable.
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Not sure what happened to the thread. Feel free to call me and I will share my experiences with friction loss.
 
Lenny Schrecengost said:
I recently read a post about using a 1/2 hose because the pwer was loosing pressure when he went to 7 or 8 gpm. I can not find it. I think it was on this board or the UAMCC. Can anyone help me find it. We are getting ready to get a larger trailer and put 2 machines together to get the volumn and I want it to work as good as possable.
Click to expand...


Here they are, you have your pick from either.

http://www.propowerwash.com/board/upload/showpost.php?p=136786&postcount=22


From Tom of Liquid Heat Az.
http://www.dultmeier.com/pdfs/tech-library/02Water8.pdf
 
It was well worth it when I went to 1/2", a big difference and noticeably faster at 8.5+. I would highly recommend it at 8 gpm or more. Just toughen up that first few weeks and you'll be used to it, then when you use a 3/8" it feels like spaghetti!
 
Reduced Pressure

If I remember correctly you will have Reduced Pressure when flowing a lot of gpm's through longer hose or smaller hose when Pressure Washing. Here is what I remember about losing pressure:

Using a 3/8" hose for 8gpm you will lose about 300psi per 100' of hose.

Using a 3/8" hose for 5.5gpm you will lose about 134psi per 100' of hose.


So those of us using 200' of 3/8" hose will lose a lot with the 8gpm when pressure washing but I am not ready to go and get the 1/2" hose yet, probably after the beginning of the year but not right now.

Hope this helps.
 
Lenny Schrecengost said:
Thanks guys, I see a loss but not enough to go to 1/2" hose
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How much flow were you going to run in the 3/8" hose, anything over 300 psi friction loss is a lot in my opinion.




Look at it this way:

300 psi loss at 8 gpm translates to = (8 X 300 )/1100 = 2.182 HorsePower loss.

Consider the loss in cleaning impact, because the pressure now at the end of the hose is 3200 psi,

Think about this,...Which nozzle would flow more:

A 8.5 nozzle in a wand and 3200 psi on the inlet side of the nozzle?

Or a 8.5 nozzle in a wand and 2800 psi on the inlet side of the nozzle?

Where does the rest of the water go?

So when you have major friction losses in you pressure washing system you loose in more ways than one:

HorsePower
Flow
Pressure
Cleaning Impact
Possible Unloader Wear

There is only one gain to be had by high friction loss in the above pressure wash system, it may even assist in better cleaning.............:scratchhead: --------!!
 
Guess it depends on what you are cleaning. If I did flat work it might be an issue if I lost a few hundred psi. I wash houses and buildings at low pressure so it is no problem for me. Not worth the 1/2 inch hose. We run surface cleaners and turbo nozzles on breezeways and residential driveways. I use tips for 6 gpm machines instead of 8 gpm to make up the difference.
 
offdutyfireman said:
Guess it depends on what you are cleaning. If I did flat work it might be an issue if I lost a few hundred psi. I wash houses and buildings at low pressure so it is no problem for me. Not worth the 1/2 inch hose. We run surface cleaners and turbo nozzles on breezeways and residential driveways. I use tips for 6 gpm machines instead of 8 gpm to make up the difference.
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Very true, I was thinking "roncrete".
 
offdutyfireman said:
Jim, you probably know but I was referring to garage cleaning Jim, not you.
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No worries bro. Dad always told me, "Junior, don't matter what people think about you, just as long as they're thing about you".
 
This difference is huge. Now that I have the 1/2" hose, my production is better than 50% improved, rinsing takes half the time and although I'm not jogging behind my spinner, I'm moving at a much better pace.

Firedude, if you're not doing flatwork, no need to worry. 2 paperclips for you.
 
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