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  #1  
Old 08-05-2014, 09:47 AM
tmramrod91 tmramrod91 is offline
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sprinkler overhaul-switch from rotors to rotators

Hi All-

I recently put in a fence in my yard and it has required me to move around a lot of sprinklers, adjust throw distances, etc. I've had the house about 2 years and the yard is in ok shape but I want to get it in great shape. I drilled a water well and have been watering heavily, but I'm still getting brown spots underneath the arc of the rotors. They system is probably 10-12 years old with RB 5000s.

I'm in an area with very heavy clay soil, on a slight slope so runoff is an issue.

Question is-can I switch from RB 5000 rotors to an entire Hunter MP rotator system? Most of the rotors are spaced between 17-25 feet apart, but none more than 25 feet. There are some rotors in the middle of the yard to make up for the lack of coverage from the perimeter rotors.

Can I get away with using the MP3000 series for the longer throw distances? I've read they only require 30% overlap?
I was thinking of using the PRS with the 6" pop up due to the slope. The well pump is 1HP and water pressure is not an issue at all, in fact it is probably too high, which is my thought behind the PRS bodies.

I'm going to be investing a lot of money and sweat into amending the soil with top soil and compost and overseeding this fall, so I want to make sure my sprinklers are dialed in before that time comes. Cost is not a big concern, I am looking for quality.
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  #2  
Old 08-05-2014, 10:41 AM
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Wet_Boots Wet_Boots is online now
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Maybe do an audit of the existing system coverage, because the new sprinklers won't fix built-in problems of improper head spacing or incorrect nozzles. A system of 5000 series rotors shouldn't have to have too high head pressures, because nozzles can be upsized to bring down zone pressure.

Really poor drainage can be compensated for by way of cycle-and-soak programming.
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Old 08-05-2014, 10:50 AM
tmramrod91 tmramrod91 is offline
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Thanks for the reply. I will probably look into new nozzles before redoing everything. The coverage is good, the main issue is the brown "crop circle" for the first 8-10' from the rotor head. It has become even more of an issue with the increased pressure from the well pump. I installed an entire mp system a few years back and was impressed by the coverage and have been thinking of doing it myself but didn't want to add too many additional heads to get adequate coverage, but with the 3000 series I think it just might work.
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Old 08-05-2014, 12:12 PM
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Wet_Boots Wet_Boots is online now
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Investing in a pressure gauge with a pitot tube might be in order, so nozzle pressures can be measured. Sometimes an increase in pump horsepower doesn't result in performance improvement in the field, because the increased flow from the pump has to travel through plumbing that is now a size too small, robbing the heads of pressure.

Sight unseen, we are indulging in guesswork, while advocating careful measurements of pressures. The dry circles around heads most often occur from poor water distribution that low pressure creates, although very high pressure sometimes generates fogging that can drift away in a strong breeze, with adverse effects on distribution.

If it happens there is low field pressure, there is no shame in adjusting the nozzle screws to create more in-between coverage. Also, it may be possible to adjust the pump's pressure switch for a higher operating range, so that higher supply pressure can overcome increased pressure losses in the system plumbing.
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Old 08-05-2014, 02:25 PM
Kiril Kiril is offline
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Quote:
Originally Posted by tmramrod91 View Post
The coverage is good, the main issue is the brown "crop circle" for the first 8-10' from the rotor head.
If the coverage were good there wouldn't be "crop circles". You need to properly design a head to head system if you want to do it right.

Oh and a note on your soil. If your are doing all that amending to improve drainage don't waste your time, sweat, or money. You will simply be moving your drainage problem down a till depth.
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Old 08-05-2014, 07:11 PM
ArTurf ArTurf is online now
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[QUOTE=Kiril;5088787]If the coverage were good there wouldn't be "crop circles". You need to properly design a head to head system if you want to do it right.

Ditto,
Changing to MP's won't solve this problem, although they might be more appropiate for smaller throws vs choking the chicken on a rotor approach. Find out your actual available pressure/gpm. MP's only needing 30% overlap is incorrect as in any head.

Run off, program multiple shorter run times and use check valve heads. Low head drainage is a sin IMO.
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Old 08-06-2014, 10:05 AM
tmramrod91 tmramrod91 is offline
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I probably should have thought of this initially-how much of this issue could come from the risers not going up high enough to clear the grass? The worst areas seem to be where that is occurring. There are a few other issues that is probably due to poor coverage but I think adding another head will cure that. I'll need to check the PSI but I can run a hose off my well line with excellent pressure while a station is running with no noticeable difference in throw distance, so I am thinking my pressure is fine but I'll just need to confirm what it is at.
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Old 08-06-2014, 10:36 AM
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Rotor heads that pop up only an inch-and-a-half can still provide full even coverage, so stay focused on pressure for now.
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  #9  
Old 08-06-2014, 07:01 PM
tmramrod91 tmramrod91 is offline
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I measured psi on 3 heads in 3 zones with pressure gauge (no place in town carries a pitot gauge)-pretty standard 40-50 psi on all 3, with them being all almost right at 45 psi, which I believe is ideal pressure for the RB 5000. I adjusted the throw to get better head to head, which will cure some of the problem but I also do have more over spray because of a weird shaped yard. There are 3 rotors in particular that have minimal head to head coverage because of probably poor design. I'm at 7 rotors per zone right now and I'm not sure if adding another head per zone will have a big impact on psi?
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Old 08-11-2014, 09:31 AM
enorl76 enorl76 is offline
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Quote:
Originally Posted by tmramrod91 View Post
I measured psi on 3 heads in 3 zones with pressure gauge (no place in town carries a pitot gauge)-pretty standard 40-50 psi on all 3, with them being all almost right at 45 psi, which I believe is ideal pressure for the RB 5000. I adjusted the throw to get better head to head, which will cure some of the problem but I also do have more over spray because of a weird shaped yard. There are 3 rotors in particular that have minimal head to head coverage because of probably poor design. I'm at 7 rotors per zone right now and I'm not sure if adding another head per zone will have a big impact on psi?
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Too many more rotors per zone and because of the additional flow, you'll be fighting with friction loss/PSI loss through valves and fittings because of the higher flow.

7 (depending on nozzles) is probably the max on 1" valves, you'll start encountering water hammer and various other undesirable behaviors.

If you need to add more, drop ALL the nozzles down by one size, which will reduce flow, (and subsequently require longer run time)
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