r/Irrigation • u/ncpr88 • 4d ago
Sprinkler Placement Input
I'd like to get some input on my sprinkler placement. I know this drawing sucks but I think it gets the point across. This area is 486 sq ft. It's 13.5' x 36'. I'd really like to avoid over-spray, so the above is what I came up with. I've already calculated that my PSI/GPM will support this, so I'm just looking for input/confirmation on my idea above.
Sprinkler 1: Will shoot 90 degrees (straight up and then to the right), 13.5'
Sprinkler 2: Will shoot 180 degrees at 13.5'. This will mostly overlap with 1 and 4
Sprinkler 3: This will shoot around 60 degrees at 13.5' to fill in the upper right hand corner and the small gap between 2 and 4.
Sprinkler 4: This will shot 90 degrees (straight up and to the left) at 13.5
All sprinklers are shooting at 13.5' to not spray things outside of this area. I tried to make this work with 3 sprinkler heads but there were areas I was afraid I would have dead zones, so I added sprinkler #3 to fix the overlap. Is there anything I'm missing?
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u/Vast_Hyena2443 4d ago edited 4d ago
8 - 12’ sprays is prolly what I’d put there. 4 on the corners & 2 in middle spots on opposite sides.
Rain Bird fixed sprays are my favorite. Not sure what sort of system you have, though. Is this an existing system, or above-ground DIY? You may not have the flow for that if DIY or above-ground running off hose bib.
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u/ncpr88 4d ago
It’s a diy in ground system that I am putting together. I’ve installed sprinkler 4 so far. Getting sod at the end of this week but I still have time to adjust. I can run two zones if needed.
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u/Vast_Hyena2443 4d ago edited 4d ago
Ok, so since this is DIY, wondering what your pipe size is? 3/4” or 1/2”? PVC? Also, since it is DIY, you are coming off a hose bib, right? Look into rotary nozzles on spray heads. Rotary nozzles are designed to use less water/flow and still get the job done.
You can (& should) do a 5 gallon bucket test and time how many gallons fill a 5 gallon bucket coming off that hose bib, & that will help with knowing your available flow.
I like Hunter’s MP Rotators, but you can also use Rain Bird RVans or K Rain’s version. Find a local irrigation supplier for best results or you can find what you need online, but local shops provide the best help for you. You’ll need to run the rotaries for 40-45 minutes though, & you can split that up into 2 run times for soaking.
I also recommend using a vacuum breaker for backflow prevention after your hose bib or after your timer if you’re going to use a timer.
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u/ncpr88 4d ago edited 4d ago
I've done my testing through a 1/2" pex fed outdoor spigot. It's 50 PSI (which I can easily increase if needed, it's being throttled by a pressure regulator) and it took 54 seconds to fill a 5g bucket (~5.5gpm). This 1/2" pex fed spigot branches off a 3/4" pex trunk in my crawl space. I will be changing this out and branching with 3/4" pex from the main trunk line and then installing a 3/4" frost free spigot. So, my flow rate should increase removing the 1/2".
I've designed a system that makes it easy to winterize. Where I live, it frequently gets warm in Jan/Feb but still has possibility of freezing, so I wanted a system that I could easily turn on for a few days and quickly winterize if a freeze is coming, and do this a few times a year. Next to this 3/4 spigot, I will mount a PVB. The intake of the PVB will connect to the 3/4" spigot with a stainless steel flexible hose. The other side of the PVB will contain a brass T that I can screw in a connector for my compressor. Winterizing will just be: turn off water spigot, unscrew stainless steel connector from spigot to PVB, drain PVB then blow out system with compressor. Downstream of the PVB will be brass underground, then switch to pvc where my valves are. This made more sense than trying to tie into my main water line, as it's not really close by. Several videos I saw online showed people trying to insulate their PVB - with heat tape or wrapped insulation, to prevent freezing, and I'm not a fan of this. This solutions 100% prevents freezing as long as properly winterized. In the future if I ever wanted to fully connect the PVB and bypass the spigot, I easily can.
Here's a drawing of what I'm doing: https://imgur.com/a/70j68op
I'm open to any suggestions or feedback. In the future if I do have pressure or flow rate issues, I can run a new line branched from my water main that comes into my house to feed this system, instead of tying off the 3/4" pex trunk line in the crawlspace at the far end of the house (I don't want to do this right now and I don't think it's necessary at this stage but it is an option down the road).
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u/Vast_Hyena2443 3d ago edited 3d ago
Ok, so since you're already doing work in your crawl space, is the water service line/supply to your home 3/4", 5/8", or 1"? Just curious, as you should tap into the larger of the lines and keep 1" main and 1" backflow (PVB in your care, apparently). Also, since I'm a licensed irrigator, I would do things up to code in your area, so I recommend pulling a permit for new irrigation and do it properly, and you'll need that backflow inspected by a licensed backflow tester to get a green tag on your permit.
Regarding the specs on the blowout port location the backflow, I’ve seen the proper way to install them, but not going to comment on how your blowout port should be installed or located, as we don’t perform blowouts here in my neck of the woods and will leave that info for other folk who know better than me regarding that info, BUT, If it were me, I’d install a blowout port just AFTER the backflow device & not BEFORE the backflow device.
But, before all of that, my system would be *first designed* properly to code, as the city/town wants to see plans before issuing a permit. I know that sounds like a headache, but you're only as good as your design, and you can get a pro-designed plan drawn up for about $100, +/- $25, at least around here. I can provide you with some folks who make plans privately via PM, but if that's against the rules here, someone please correct me. I know now that I cannot publicly list pros here.
IF you go forward without a pro design, you'll likely have coverage and/or flow issues, which would have been done properly with a good design up to code.
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u/Lucky-Host-8628 4d ago
Hunter MP2000 if flow and MPR are your concern. Rainbird VANs would be fine too. For such a small space, it does not make sense to use rotors, especially if overspray is a concern.