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czqeiclr

New Member

1

Thursday, September 29th 2011, 2:34am

Which nozzle?

Hi there,

First post here.

I'm looking to set up nozzles in a fairly large lawn area where existing sprinkler heads are about 24 ft apart. I wonder which kind of nozzle would provide the following features:

- works w/ somewhat low water pressure (28-30 psi)
- provides adequately large coverage (24 ft for existing head-to-head distance)
- clean and good edge coverage
- does not require 100% head-to-head coverage (has nozzle head coverage already, i.e. no dry spots around the nozzle head)
- does not take too much time to provide adequate water precipitation


I've been using some Rainbird rotary nozzles but in practice w/ the low water pressure

- it barely covers enough (21 ft w/ current water pressure),
- seems to have some head coverage so doesn't require 100% head-to-head coverage so that's good
- coverage along the edge is poor -- spray length is very short when it gets close to the edge => dry spots along the edge. Only workaround is set wider arc => overspray.
- takes double the time to provide enough water for the lawn. For the front lawn alone it takes 5 hours.

I tried the Hunter MP Rotator MP3000 but the edge coverage issue is similar (much shorter length when close to the edge).


Any great ideas pls feel free to provide.

I've heard about Toro's Precision Spray Nozzle, but it'd only cover 15 feet -- not enough for my situation (24 feet required).

How about Toro Precision Stream Rotating Nozzle? Does it cover correctly along the edge--or not?
http://www.toro.com/irrigation/precision_rotating_nozzles.html

Or Rainbird rotors: 3500,5000 series?

Do gear-driven nozzles last just as long as non-gear driven nozzles? More maintenance (like debris/minerals)?


Thx.

This post has been edited 9 times, last edit by "czqeiclr" (Sep 29th 2011, 4:12am)


Mitchgo

Supreme Member

Posts: 502

Location: Seattle

2

Thursday, September 29th 2011, 7:13am

Is that pressure you stated your static pressure or dynamic pressure. This is the most important thing to know right now.

If its your static pressure then there isn't much else that can be done Given the design. You would have to split and add zones to get what you are looking for. Or a booster pump is in order for the system.

If its dynamic , this is more workable but still difficult. The thing is any kind of rotor swap out , they use more water then your curent heads. Re designing the zones may still be in order. How many sf is the lawn . 5 hours ?

This post has been edited 1 times, last edit by "Mitchgo" (Sep 29th 2011, 7:21am)


Wet_Boots

Supreme Member

Posts: 4,044

Location: Metro NYC

3

Thursday, September 29th 2011, 9:21am

First get your coverage, then worry about how long the watering takes

czqeiclr

New Member

4

Thursday, September 29th 2011, 12:23pm

The static pressure at the main w/o any sprinklers turned on is about 60 psi. With the Rainbird nozzles turned on the pressure is between 28 - 35 psi (depending on which zone).

The shorter coverage issue I am seeing seems to be along the edge where the spray length shortens significantly, leaving a strip of area along the edge where there's no overlapping coverage.


When I changed out to use MP3000 the edge coverage issue is similar, the edge coverage seemed slightly sharper (although still obvious) perhaps because the MP rotator had lower gpm for same coverage area, hence less pressure drop per nozzle.

The shortage of edge coverage can be fixed if I widen the arc further to cover more than the edge on the MP rotator (I could not do this w/ Rainbird's rotary nozzles since they are fixed arc). But then there'd be overspray.


The spray area from a rotary nozzle seems to look more like elliptical than circular now (along the edge).

Wonder, if the pressure is good enough the edge should be sharp and clean on the Rainbird rotary and the MP rotator nozzles? I talked to someone in an irrigation store and they mentioned MP3000 has the edge coverage issue more than MP2000/MP1000. They suggested to widen the arc to allow a bit of overspray also.


When asked about Rainbird 3500's, they said that Rainbird 3500 series has cleaner edge than the Rainbird rotary nozzles as the stream goes both directions. It does require 45 psi to have a nice spray coverage, for 28-30 psi there would be uneven coverage the first 2/3 of the area.



I called a Toro rep (2nd Tier) and he said Toro's Precision Rotating nozzle by nature can't provide a clean edge compared to the spray nozzle. He also suggested overspray with wider arc out on the sidewalk so the spray length extends enough when it gets to the edge.

This post has been edited 23 times, last edit by "czqeiclr" (Sep 29th 2011, 10:00pm)


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