I’m getting tired of dragging hose around this place and would like to install several yard hydrants in key locations. I know the mechanics of assembling the system, but not the limiting factors: what size tubing, how far can I go, etc.
I have an existing dedicated well (supplies nothing else) with a 1HP jet pump and 1″ outlet. Currently it goes to a pressure tank and then one 3/4″ faucet that I run hose from. I’d like to bury a bunch of poly tubing below the frost line and install hydrants at remote locations on the property.
Can anyone tell me:
1. How far can I run lines without dramatic pressure loss. I was planning to use 1″ tubing and then reduce to 3/4 at the hydrants.
2. Is it better to home run the lines or put them in series? It is unlikely that more than one will be in use at any given time.
In an ideal world, I like to run lines 5-600 feet in multiple directions, but don’t want to waste time and money if that can’t be supplied by the current pump.
Any advice is appreciated.
Replies
It's about head sizes and coverage
Spinrkler systems (underground irragation systems) can put a lot of water out a long waY FROM THE SOURCE.. i HAVE A 2 hP PUMP INTO THE LAKE AND SOME OF MY LINES ARE WELL OVER (oops) 300 ft. long. I generally run about 7-9 heads on it but I've broken it into 3 zones (with each 7-9 heads) the big rotators use the most water and cover the biggest area but aren't very efficent.. The fixed head sprinklers do the best job except for trickle soakers which lose very little to evaporation..
The trickle head soakers work great except they plug up extremely easily and it takes a long time to discover the problem. At least with spray heads you can tell instantly when they are plugged..
With only a 1 Hp coming up from a well I'd be reluctant to put more than 5 heads on a line and break out the zones accordingly. You can either manually switch zones or do as I do which is have them on a timer. The real issue is blow out.. I do it every fall with my own compressor and it takes me about 45 minutes or so but I set it up right from the start to blow out.
Common here to run 1" ABS up to a thousand feet long over hill and dale
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The way you'll be using this system (yard hydrants, not sprinkler systems; one hydrant at a time being used), you should not have any problem using the existing pump and 1" outlet. Running the hydrants in series will be fine, too.
Just for peace of mind without hurting the cost much, you might consider running the new lines in 1-1/4" instead of 1", even tho you'd be tying into 1" at the source. Doing this will reduce your friction loss over long distances and improve delivery at each hydrant. It also gives you better flexibility for future changes or additions.
I ran 1-1/4" but the price was quite a difference since there's not as much sales volume in 1-1/4" as there is in 1" and 3/4".
The pressure loss is governed by the flow rate, the pipe diameter, and the friction factor for the pipe.
If you do a Google search for "friction loss plastic pipe" you should find several tables that tell you how much friction loss per hundred feet of pipe you will have at various flow rates. This is one of my favorites: http://www.engineeringtoolbox.com/pressure-loss-plastic-pipes-d_404.html
The sprinkler manufacturer's site should tell you how much volume the sprinklers use, and what pressure they need. From that, figure out how much water you will be using, and how much pressure you need at the hydrants.
Your pump should have data on how much it flows at different delivery pressures. You also need to figure in the differences in elevation from the pump to the hydrant nozzle.
Once you have all the data, it doesn't take long to take a couple of tries, and see what size pipe works.
Say you need to deliver 8-gpm, 600-ft, and the allowable head loss is 10-ft of water head. So, you need a pipe that will loose less than 1.66-ft/100-ft at 8-gpm.
At 8-gpm, 1-inch pipe looses 3.9-ft/100-ft, so it is too small. But, 1-1/4-inch pipe looses only 1.0-ft/100-ft, so it will work.
I just ran 400 feet. I started out with 200 feet of 1 inch, then 100 feet of 3/4 inch and finished with about 100 feet of 1/2." I didn't calculate and I'm using a drip system with about 100 emitters. They all seem to work fine.
If your current well & pump config is working using garden hoses there's no reason that you'll have any trouble using yard hydrants. The bigger you go the better it is when figuring pipe diameter to a point so the budget can drive the choice there.
I used 1-1/4" PVC water supply to run to the hydratns and as that was being reduced I installed a Tee (& capped it) at the base of the hydrant connection for future sprinkler expansion. They are all run in series.
Don't be too cheap on the placements of the hydrants. I've found it's better to have 1 more in a convenient location while you have all the equipment than it is to add it later.
You ought to be able to boost the pressure on the tank & pump pressure switch to increase your supply pressure if you need to.
I love a thread that comes back with all kinds of varieties of "yep, that will work" instead of a million reasons why it won't. The friction loss table was just the thing I was looking for, and I'll be checking into the difference in price to go to 1 1/4" instead of 1".Thanks to all who responded!=====Zippy=====