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3/8 hose vs 1/2 inch test

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I got another 10 gal. machine with 31 horse power engine and a 660 Cat pump and it rocks. We put 300 feet of 3/8 hose got 2500 psi. We then put 300 feet of 1/2 inch on and got 3000 psi. The 500 psi diffrence is not that much for me to use the 1/2.

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Brain,

When you have time check the amount of water out put from both and see if it is close, I know that using 5/8'' hose is not as good as 3/4'' hose. I have alway wanted to know about that glad that someone tested it out.

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In the fire service, we figured an inch and three/quarter hose put out twice the GPM as a inch and half hose. If the amount of water is important to your work, the larger hose may be the best buy.

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To some degree that is true, but off a fire hydrant is one thing. Off a pressure washer you are going to hit diminishing returns real quick because the pump is running at a fixed / governed speed and is only going to pump so much water out the 3/8 outlet from the pump.

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To some degree that is true, but off a fire hydrant is one thing. Off a pressure washer you are going to hit diminishing returns real quick because the pump is running at a fixed / governed speed and is only going to pump so much water out the 3/8 outlet from the pump.

Mine has a 1/2 in outlet and my bypass is 1/2 inch as well as is the unloader input and output, 1 inch lines from the tank ect.....

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I called cat and they told me that I would lose 400 psi for every 100 feet of line with the 3/8 and 100 psi for every 100 feet of 1/2. But my test showed that it was about 200 psi and maybe 50 psi. I do not know about the water flow but it did not seem like it was that much of a difference. We do more buildings and homes so I was looking at how high we can shoot the water and chemical and it was really no difference. The surface cleaners already fly.

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I know that it goes down in water flow but it did not feel like it was that much of a difference and I wanted to share it.

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Yes it is a good spot. Be careful of any hoses. We broke a connector in the gas line when we first did it and then we made sure it was all out of the way.

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Cool test. Everyone would have bigger biceps pulling 1/2 anyway...

Its is a "tug of war" full body workout.

The 1/2" hose may come in handy, if you ever need to go out more than 200 feet with 7 gpm and more, requiring pressure (at least 3000psi) at the gun.

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Normally 8 GPM and below you use 3/8" high pressure hose, 9" GPM and above you use 1/2" high pressure hose. Using these sizes you lose about 1 psi per foot. The actual loss depends on how many elbows you have and how straight is the hose (is it off the hose reel in a straight line). Also type of rubber or synthic material the hose is made of effects the pressure loss. Synthetic hose link Synflex 3R80-06 has the least resistance that I have measured. It was popular hose before manufacturers started making hose specifically designed for pressure washers. Above about 220F the inter lining would start melting and the ends would blow off. If you were watching for this failure you could actually watch the end start to slide off the hose before it blew off. The hose was designed for Hydraulic Fluid.

The longest length of 3R80-06 that I ever ran was slightly over 1,000 Feet to clean Miller Brewery Tanks for making Beer. They were about 10' in diameter X 125' long, stacked 3 high. It was a Union Shop, so all I did was run the equipment while Union Steel Workers did the work.

Edited by Robert Hinderliter
typo

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Brian, did you find a downstream injector that will work with 10gpm? If so, what brand and where did you get them.

Thanks.

We do have 4 10 gal. Machines and they all have cat pumps that i run the chemicals thru the pump. I know people do not like this but it is the best and fastest way for us. We have 300 feet on all reels and we add more hose at some jobs. And the downstreamers do not work with that much hose. I do have one 10 pump that is not a cat and we do have a downstreamer on it with a pump that helps pump the chemicals thru the hose but it does have some issues.

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Normally 8 GPM and below you use 3/8" high pressure hose, 9" GPM and above you use 1/2" high pressure hose. Using these sizes you lose about 1 psi per foot. The actual loss depends on how many elbows you have and how straight is the hose (is it off the hose reel in a straight line). Also type of rubber or synthic material the hose is made of effects the pressure loss. Synthetic hose link Synflex 3R80-06 has the least resistance that I have measured. It was popular hose before manufacturers started making hose specifically designed for pressure washers. Above about 220F the inter lining would start melting and the ends would blow off. If you were watching for this failure you could actually watch the end start to slide off the hose before it blew off. The hose was designed for Hydraulic Fluid.

The longest length of 3R80-06 that I ever ran was slightly over 1,000 Feet to clean Miller Brewery Tanks for making Beer. They were about 10' in diameter X 125' long, stacked 3 high. It was a Union Shop, so all I did was run the equipment while Union Steel Workers did the work.

I have heard most say 9 gpm ^ ;.... 3/4 coils and 1/2" hose.

Robert, why does the industry use 1/2" coil as the base standard and not 3/8" in low flow heaters?

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Because of production expense, 1/2" will do both jobs. Coils are about 175' long and that creates a lot of pressure loss. The cost savings is not that great after you have make two sizes. Smaller Coils are found in light duty Dixie Cup Machines.

Sent from my Dell Streak using Tapatalk

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