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Discussion in 'Homeowner Assistance Forum' started by hadfield43, Jul 30, 2013.
What is a POC?
Here you go - and high level landscape overview
Thank you all - for the help.
It's really excellent that people are willing to take the time to write these responses and having a resource to go to. I can't even tell you how much it means to me.
If you look at the google image I was just going to put a manifold where it says manifold with 11 valves (dumb now I realize), instead mainfold 1 will have 6 and mainfold 2 will have 5 (just for the central between the driveway), the idea will be to run 1" PVC to manifold 2 from manifold 1.
I will retest the central area to see if I can get 5 heads instead of 4 working in each zone, and if so reduce the number of zones to 3 grass zones + 1 dripper zone. At present I can only get 4 heads per zone at 26 feet - 30 feet per head. I am using Rainbird heads that are specified to get 26-32 feet when proper flow is provided (4 heads is okay, 5 so far has not been, but that was running 3/4" pipe from manifold 1, as opposed to 1" PVC as suggested).
The fifth zone will be for a dripper loop for the three plant/tree/shrub beds illustrated in the CAD drawing.
It is worth noting that the central area between the driveways is graded so the middle long horizontal part is about 8 feet higher than where it meets the driveway and maybe 2 feet higher than where it meets the road. I made sure to put my backflow at least a foot higher than where the highest head will be.
Correction, the middle long section is about 5 foot higher (not 8 foot) and it's about level with the road. It's about 25 foot long from the lowest point to the highest point.
I don't know what your zones indicate on your landscape plan, but if they are supposed to be hydrozones you will need to rethink. Keep in mind, a proper landscape design will group plants with similar requirements (water, fertility, soil type, exposure). Each of those groups will represent a major hydrozone. You then refine those major hydrozones into smaller hydrozones giving consideration to sun/shade, wind, slope, orientation (N, S, E, W), soil variations, etc... if needed. This will help get you started down the right path.
Personally I would be leaning towards 4 manifolds of 3-4 valves per manifold. IMO you should be able to easily observe the area the valve controls from the valve location with minimal walking.
I don't know what you mean by testing heads, but I highly recommend you do not even begin to design your system in this fashion. You need to collect some hard numbers on flow and dynamic pressure at your POC (point of connect) and design your system from that point.
Wow I cannot even tell you how much I appreciate your help.
The zones are not hydrozones as you mentioned, they are local HOA terms.
I am pretty confident in my selection of plants because I consulted with local landscapers and also am basically copying neighbors. I have also had my soil tested and prepped the grass areas based on this with sheep compost (1"). I am not doing shrubs and trees until next year, so will probably apply a different prep based on what is advised at the time, the good thing the soil analysis should be just as good then. There are very few areas where we don't get full sun, which I guess has its pros and cons. We get A LOT of wind out here so some of the plant types I originally had in mind had been changed to account for that.
I think your idea of going to 4 manifolds might be a bit overkill for what I am doing, I keep looking at my plan trying to figure out where I would put in a fourth one and I just can't see any real benefit, but you got me thinking hard about 3 and am pretty sure I will do that. Especially putting one on the North Side running down from Manifold 1.All 3 would stem out running from the central backflow (I guess I will need several PVC Tees to make that work). Basically would have 4-4-3 setup (sounds like a soccer setup).
I think your minimal walking rule of thumb makes a lot of sense. From a grass point of view, that will certainly be the case if I go to 3, my drip zones will run a bit longer, but would all be pretty close (within 75ft)
From a testing point of view, I did the traditional PSI and flow readings and that told me I should be fine getting 4 heads per zone. I just wanted to try it in different areas of the plan (seeing is believing) and I built an above ground 3/4" test and 4 worked well, 5 did not work - just as expected. Of course this test didn't account for the concept of adding more manifolds but I don't really see how that makes a difference, especially because I will be upgrading to 1" pipe. I guess the main difference could be the possibility of more heads per zone, but I think that would be a risky assumption?
My PSI runs between 70-80 and the flow is about 9GPM.
I guess some questions:
Every time I talked to you I get a better design, would you mind answering a few more questions:
1) I am planning to run PVC to the manifolds, then poly from there. Make sense to you?
2) Since the PVC will be 1" to each manifold and each manifold now will be close to each grass zone do you think it's overkill to then put in 1" poly or do you think 3/4" is okay?
3) Since I am going to 3 manifolds, I will have longer wire runs over 100ft, do you think 18 gauge wire will be okay (I have heard yes, but wanted to get your opinion).
I am a big proponent of using plants that are not only appropriate for the region, but also for site conditions. You should be careful not to stray too far away from using plants that meet these conditions, especially concerning soil conditions.
See attached pic for a possible 4 manifold setup.
I would consider using a larger pipe size for your supply main (ex. 1.5"). I typically will use 1" on main laterals and tee off of that for each sprinkler. Regardless, you need to crunch the numbers to determine how to lay it all out and what the appropriate pipe size is.
Recheck your numbers, that flow rate seems low to me.
I don't live in poly land, but if I did, I would run the supply main in PVC.
Already noted above.
I wouldn't push it more than 600 feet with 18 gauge.
You are a great guy - thank you so much for the help and the diagram, that was excellent of you to take the time.
I guess the one area where I am feeling a bit confused is on the numbers part.
I will remeasure the flow as I agree it didn't seem to make sense that it would be low.
Can you point to a website or tool or something that helps with the more precise calculations you speak of?
Again - I know you have spent a lot of time with me and doing so freely says a lot about you, I will be sure to try to pass-it-on with something.
General Manufacturer Design Guides,
There are more links in the menu to additional resources. These are a couple of good starting places to get information and basic instruction on design.
For drip irrigation, start with the best, ignore the rest.
Netafim Design Guide for Techline CV
There isn't really an easy web calculator for measuring flow. There are various methods which you can use, a flow meter being the most accurate. If you have a water meter, then it might tell you the current flow through the meter. Best way to measure available flow for irrigation would be to measure it at the POC. In your case you may want to put in your PVB or RPZA or whatever backflow is required in your area, then measure the flow on the downstream side of the backflow.