What do the run times look like to get the same amount of precip from the rotary nozzles?
I transitioned mostly from spray heads @ 1.5 in/hr to the MP rotators @ .45 in/hr @ ~40 psi… So run times are roughly 3x.
Thanks for confirming. My grass suffered a bit last year as I never bothered to verify the rates. 20 min run time to 60 minutes hurts a lot with 16 zones…
Yep, I can see your point. Only 5 spray head zones for me and 2 drip zones so i just moved my schedule start back to 4am to compensate.
Can always combine zones, if they are similar in terms of sun, soil, and vegetation. The slower flow rate makes it possible. I believe that the rachio (and most controllers) support 2 valves per zone.
I was not a big believer in the MP Rotors until my current home. I live in Texas with lots of rock and clay. Additionally my house is on a hill and I have between 7-18% grade throughout my yard.
The MP Rotors are awesome for these types of settings. The ground takes a long time to absorb water and since the yard is so steep it’s hard for the water to be absorbed. Using the rotors allows for the time to get the water into the soil.
My only caveat, as others have said, it twk s 3-5x longer to water. If you have any leak anywhere, such as the gasket with the pop-up you could have a large water bill. Definitely recommend visually checking heads up that very month.
I had a heck of a time chasing a high water bill and a flooded yard, only to find that half of the wiper seals on the sprinkler bodies were trashed. Doesn’t make much of a difference when you are watering for 5 minutes, but 45 minutes makes a bit of a mess!
Definitely less runoff because rotating nozzles apply between .37 and .6 inch per hour. Great solution where there are a mix of rotors and fan spray nozzles in a zone. Much better wind resistance than fan sprays. I am a huge fan of multi stream rotating nozzles. The decreased precipitation rate means more water gets on the landscape. Misting is not as much of a problem with rotating nozzles. I have recently removed all my MP Rotators and replaced then with Rain Bird rotary nozzles. They are great.
MP rotators can save water in several ways:
- Low water pressure at far end of pipe run from valve.
- Spray heads spaced too far apart.
- Atomization of spray from high pressures, especially near valves.
- Run-off from clay soil not being able to absorb the high precipitation rates of Rainbird heads.
All of these produce uneven watering. Uneven watering causes you to increase overall watering levels to eliminate the brown spots, but this results in overwatering of the areas that are not brown. By making the distrubiton of water more uniform, the tendency to “overwater” to compensate for dry spots is significantly reduced.
MP heads have 1/5 the precipitation rate of comparible Rainbird spray heads. If an original irrigation system has additional heads added to extend the area irrigated, then the line diameter may be inadequate for supplying this total volume of water without a significant pressure drop. A low pressure at the far end of the line will reduce both the precipitation rate AND the radius throw of the spray heads furthest from the valve causing less watering and dry spots.
MP rotators solve both of these problems by reducing the total flow of water through the pipes, eliminating pressure drop problems. Also, the available of MP radius up to 28’ allows the correction of spray heads that have been placed too far apart for optimal overlap without the costly expense of re-piping to a larger diameter or re-positioning/adding spray heads.
Finally, since MP rotators have larger droplets of water, they are less likely to atomize the water causing loss of water to evaporation and wind. They also eliminate the need to run the valve pressures high to over compensate for the pressure loss created in an undersized pipe. Pressures can be lowered, and are more uniform, eliminating the atomization.
High precipitation rates can cause run-off and wasted water if the soil cannot absorb it as fast as it is being delivered. Just look at your current system, and you will be able to see if runoff is occurring near the end of the watering period.
Another thing to consider for water savings and better performance is pressure regulated sprinkler bodies with check valves.
They will help both spray and MP rotary head by reducing pressure drop through the line. Additionally, for spray heads, it reduces atomization and produces more consistent spray patterns and for rotors, they are used to manage throw distance.
To get the most out of any upgrade, the whole system needs to be taken into consideration before passing judgement. It’s like upgrading to a better motor on your hot rod but keeping stock tires. You’ll never get the expected performance increase if the system isn’t up to par and cannot deliver it to where it matters most.
Yes, for rotating nozzles you want 40 to 45 psi at the head for optimun performance.
Everyone must realize in irrigation there are solutions for nearly every situation. If you dont like MP rotators, a great fan spray choice are Toro Precision nozzles. Their gallon per minute flow is much less than MP rotators and all spray nozzles on the market. These nozzles are avaiable in male and female thread. Toro Precision nozzles are a great solution for low pressure situations, too. No matter the radius or arc, they apply at 1 inch per hour. Give them a try.
Lightening took out my whole system this year so I installed rainbird’s yellows. I’m actually liking how little water is left behind on the grass compared to my old hurricane simulators, I hope this is going to help with some of my fungal issues.
Take out the last nozzle on the zone and you can blow out the system very quickly.
Amen. Could not have said it better.
Hurricane simulators? What did you have before?
Wiper seal issues seem worse with some brands of pop-up sprays.
Some old school hunters ripping at 5 gallons a minute.