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Friction Loss

Doug Tripp

New member
Ok I understand a little of the friction loss. Here is my question if you running 5.5 gpm 4000psi do you still have friction loss with 3/8 hose or do you notice friction loss more so when you get up in the larger pumps.
Chris,
there is always some friction loss, it's a matter of how much. Not actual numbers here just for illustration... if you use 300' of 3/8" hose with 5gpm you may lose 300 psi. Use 8gpm and you may lose 900 psi. Now switch to 1/2" hose and the psi drop for 8gpm may be more resonable at 150 psi.

Hope this helps. I'll try to find a chart tomorrow if I have time, Delco (RAHSCO) use to have one on their board if you are familar with them.
 

Jim Chesmore

New member
I have read countless posts about how higher GPM is the key to more efficient washing for everything from flat work to roofs. This is the first time someone posted anything about loss of PSI.

Dont most of the guys doing big jobs (parking garages, etc...) us the 3/8" hose?
 

Doug Tripp

New member
http://www.dcs1.com/forum/forums/thread-view.asp?tid=30&posts=1&start=1

If you follow the above link you should see a chart showing the psi loss per 100' of hose by hose diameter, BIG thanks to Larry and RAHSCO.

Jim, its been mentioned a few times before on the various BBS. I had big troubles last year when trying to clean the barn roofs. I tried to put 16gpm threw 3/8" and it just doesn't work. LOL. always fun to learn the hard way.

I use 200' of 1/2" hose and then either a 50 or 100' (depending on job) of 3/8 when doing flat work with my 8gpm machine
 

Tomdurbin

Contributing Member
Yes sir, water consumption is a major issue. Hydrant draw, or sometimes I find a 2" backflow preventor and feed 1 of my supply lines off of that. I do 1 complex, a bit over 100,000 sq ft, 2 separate 4 story buildings. Am able to draw 1 supply line off of each building and works great. But some hose bibs only put out 5 GPM.

On new projects I survey the water supply situation before we are scheduled to show-up, then I have a hydrant meter or whatever else I need to get the production I'm looking for.
Jim it sounds like your kicking Butt. Glad to hear. You might want to put a gauge between the coil and the pump. If they have a 3/8" coil you might have back pressure on the pump. If so you will go through packings but with that kind of production it might be worth the parts.
 

Jim Cooney

New member
Jim it sounds like your kicking Butt. Glad to hear. You might want to put a gauge between the coil and the pump. If they have a 3/8" coil you might have back pressure on the pump. If so you will go through packings but with that kind of production it might be worth the parts.
Thanks Tom. I've switched over to 1/2" hose and my friction loss problem has been resolved. 1/2" all the way from the pump to coil, out of the coil to the reel (Hannay) and 250' of 1/2 hose on each reel.

The gauge after the coil reads 3550 psi. At the end of the 250' I'm getting 3350. HUGE difference ! Not only in PSI but I'm getting every bit of the 9 GPM.
 

Jon Karmazyn

New member
I am glad I came across this thread. I am getting an 8gpm machine soon and will have to seriously consider the 1/2"hose for larger flatwork jobs.
 

Joshua Gray

New member
Glad I did some homework here, I just bought 2 used Hydro Tek SCU35009VAF skids from a contractor in S. Florida - lead off PWI actually - so thanks Ron. This thread was a huge time and aggravation saver.
 
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