Lawn Care Forum banner

11 zones in one manifold or 6/5 in two

6K views 32 replies 3 participants last post by  hadfield43 
#1 ·
Hi,
In another thread I asked a question which mentioned that I am planning on putting 11 valves in one manifold.

I have carefully planned the grass zones and gotten lots of advice on this. As a result I need 4 grass zones at the back and 4 at the front.

I am planning on 3 drip zones. The property is two acres.

The suggestion was to put in two manifolds to save on pipe. This is what I did in my last 2 acre property.

However, in this case I have assumed to use just one manifold which is quite wide (5FT). It wouldn't be that hard for me to split it and put in two, one on either side. One would have 5 valves, the other 6 valves.

The downside to doing this is as follows:

1) It would mean adding an extra sleeve under the 15ft driveway - this isn't that big of a deal because I am going to rent a mole device to burrow the lines under the driveway (as a side if anyone has any advice on this I would appreciate it). But this just means applying the process in a different spot.
2) It would mean an additional backflow device (another hundred bucks)
3) It means more locations where I can get a leak
4) There is no plumbing to the outside on that side of the house and to get it there sounds like a ton of work - I am pretty sure I can access that side of the house from our storage room, but it's probably at least one day of work for me, I could hire a plumber but that would probably be at least 300+ bucks at a guess.
5) The amount of pipe I would be saving would be maybe 200ft of length of 1" pipe (so perhaps 200 bucks saved there) and maybe some a couple hundred feet for the dripper pipe, which at 1/2" would be maybe 50 bucks.

Essentially my conclusion is

1 Manifold - probably would be a wash as far as cost, if I hired a plumber to put in the copper to the other side, 1 Manifold would almost certainly be less cost.
1 Manifold - probably = 1 - 2 days less work.
1 Manifold - seems easier to maintain to me than two locations

Therefore, I am trying to understand is there any other advantage in doing two locations.

Thanks I really appreciate the help in advance, I can still go either way.
 
See less See more
#2 ·
One update, so I have confirmed there is very little savings in pipe if I put a second manifold on the other side of the house a major reason for this is due to the layout of the parking and the driveway, it would essentially be longer to go around even though its on the same side of the house.

However, 5 of my zones are essentially for a very large central area between the circular driveway. In this section, there is the water tap coming into the house. I am assuming it would be possible to ask a plumber to tap into this and install a backflow prevention device sticking several feet out of the ground? Is there any reason to not do it this way. Then I would simply install 6 valves in the original location.

Help would be greatly appreciated.
 
#4 ·
Well the thought was I would be wasting a lot of poly pipe, plus I guess you have to consider friction (it's a 2 acre property) - but I have consulted with several plumbing/sprinkler people today and they all agree that I would be better off with my 11 valve 1 backflow, 1 manifold design (it's a monster yes) but due to the layout of my land, driveways, etc. I think that remains the best plan
 
#6 ·
Thank you for your reply, I wish I could agree and I am hoping if you are right you can persuade me differently. The guy I spoke to specifically focuses on backflow installation. He said to put it into the tap from the main inflow line, would require a well, a valve, drain and backflow + labor (about 1500 bucks) + a lot of electrical wire to the controller. There would be no other logical place (based on the layout of my property) to put a second manifold other than there.

By putting in the second manifold in the center between driveways, would have some positive sides (once you get over the $1,500 dollar investment) would result in me saving about 200 dollars in sprinkler pipe and having to mole 5 pipes under a 15ft driveway. It might save on a few connection points for the pipe as well (probably 5).

Keeping to the 11 valves one zone, using 1" pipe I am relatively confident I will get adequate flow (as I have already tested it).

So please please please, if you can think of how I am making this harder than it needs to be I would politely ask you to tell me how, assuming there is no other better spot for a second manifold, I just want to be absolutely sure I have the optimized plan, I have asked now maybe half a dozen people (with relative knowledge) about this and the general consensus is given the layout of my property, 11 valves, 1 manifold (with some attachable/detatchable couplings ever few 4-5 valves) is the best option.
 
#7 ·
So I guess the one other option, which all of sudden makes sense is to run PVC out under the driveway (coming from the one main backflow), install a manifold there and run poly for the five zones there (much less poly pipe - with just one main 1" PVC line), my guess is something like that is what you are thinking?

Assuming that makes sense to you (I know officially feel like a dummy and see your point)
 
#9 ·
Probably a good idea, but I have done a lot of testing of heads and will continue to test before laying final pipe, the main issue I was struggling with was the manifold locations, which now I am growing more confident that I have figured out.

I think my main mental stupidity - mental block was not thinking through the notion of just running PVC to the areas where a manifold makes the most sense (in my case a second one between my driveways). Instead I had assumed one large manifold and lots of poly pipe, as opposed to using PVC as a main line to the second manifold. This will be much less expensive and a lot less work.

Thanks for everyone's help so far.
 
#13 · (Edited)
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.
 
#15 · (Edited)
Here you go - and high level landscape overview

Thank you all - for the help.
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.

http://www.water.ca.gov/wateruseefficiency/docs/wucols00.pdf

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.
 
#16 · (Edited)
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.
 
#17 ·
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).
 
#18 ·
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 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.

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)
See attached pic for a possible 4 manifold setup.

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?
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.

My PSI runs between 70-80 and the flow is about 9GPM.
Recheck your numbers, that flow rate seems low to me.

1) I am planning to run PVC to the manifolds, then poly from there. Make sense to you?
I don't live in poly land, but if I did, I would run the supply main in PVC.

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?
Already noted above.

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 wouldn't push it more than 600 feet with 18 gauge.

Rectangle Map Schematic Slope Font
 
#19 ·
Kirill,
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.
 
#20 ·
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.
 
#22 ·
Well I think I am going to take your advice, with just a little tweaking - may as well move that one on the East Side a bit more in toward the grass or at least in the rock bed area.

The irony is the place where I originally thought to have my manifold is where there is the least need for Valves, this is just because the copper was there and I had my blinders on that the manifold needs to be near to the copper.

Will run 1.5" lines to each one.

Will look at the math stuff tonight.

Rectangle Schematic Slope Map Font
 
#24 ·
Okay, here is my calcs.

Now I did 3 tests yesterday on my Gallons Per Minute - they all hovered around 7.

Previously when I had measured this it was about 9.

I just did this with the faucet fully open, this is a faucet about 10 feet from where my copper comes out and backflow is installed.

The first file assumes I get a lack luster 7GPM

I also put the chart for the sprinkler heads I was planning to use on there

Rectangle Product Slope Font Screenshot
 
#26 ·
Here are my concerns:

1) I am pretty sure after the main line in my house is 3/4" copper, that's certainly what they installed out of the wall and is all around in the utility closet.

2) I am worried that I got different GPM readings, each time I check there is no water running in the house.

3) According to the Toro chart for the 32SA (ASSUMING my pressure is 55 - I think they mean dynamic) - I need between 1.7 and 2.2 GPM (I assume that means per head) to get 26 feet (this is how I flagged and planned each zone)

My life would be made easy if I could keep my 26ft to 26ft head-to-head plan, with up to 4 heads per zone. BUT If I am only getting 7-7.5 GPM doesn't this mean it wont work if I need say 2GPM x 4 heads (8GPM)?

Here are my questions:

1) Does the number crunching look right (assuming I have the distance and pipe types/sizes right)?
2) Should I plan on only having 3 heads per zone?
3) What do you think of me physically testing and seeing as I had with 3/4" poly previously, but now with 1" or 1.5" PVC, etc.
4) Looks like 1" PVC is fine, don't you agree?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top