# Occasionally Destructive Rotors



## noozi (Sep 21, 2020)

Hi all! Big fan of the site - it has helped me tremendously in getting my front yard re-done from scratch. It's going well outside of three problems that I've tried researching here and other sites but I'm coming up short. I've split the problems into three posts to make sure they're each in their correct board. Thank you much in advance for any guidance and for all the community has offered for the months I've used it before now. 

Irrigation Question: I have two zones of rotors. One of the zones works beautifully and one of them not so much. The zone that is having issues takes a few seconds each time it starts to re-pressurize and get the air out (I don't think that's a major issue) but seems to run well when it is going.

When I said that it seems to run well when it is going, I should clarify - that's when I am watching it. The issue is mainly in the morning when I look at how it ran earlier (6AM I believe). I don't know what happens differently from when I see it running, but there are arcs by most of the rotors where it has pushed the soil away as if it was only watering right there. I never see any sort of issues when I run them and watch so I don't know what's happening. 
In the attached pictures, the first, third, and fourth show the arcs that show up. You can see some of the area has grass which means it only did that starting today. On the second picture, you can see in the middle of the left side a pretty obvious arc.

Any thoughts? I've been running the sprinklers for a month or so now and I have never seen anything that would indicate a problem.


----------



## g-man (Jun 15, 2017)

Low pressure when you are running them can cause them not to lift/throw the same way.


----------



## noozi (Sep 21, 2020)

Thanks for the thought. Would low pressure cause them to eat up those parts of my lawn? I still can't get it to replicate the problem. And since it's the second of four zones to run in the AM I'm just plain confused.


----------



## BBLOCK (Jun 8, 2020)

just food for thought but they're not running at the same time as the shower, washing machine etc?

im currently using above ground sprinklers but I've noticed them freeze w pressure loss


----------



## Justmatson (Apr 4, 2020)

noozi said:


> Irrigation Question: I have two zones of rotors. One of the zones works beautifully and one of them not so much. The zone that is having issues takes a few seconds each time it starts to re-pressurize and get the air out (I don't think that's a major issue) but seems to run well when it is going.
> *What brand of rotors are you using?
> Don't think it matters but what is happening is your having low head drainage. It doesn't take much of a slope but after the sprinklers are off water is draining from the lowest head on that zone. < to fix, just install a check valve into the sprinkler body. They are cheap*


----------



## Justmatson (Apr 4, 2020)

As for the arcs... i believe g man has it. Looks like low pressure in that zone. 
You may not notice watching it for 5mins but after 30mins it probably causes this. 
Try going down a nozzle size on each sprinkler in that zone


----------



## RVAGuy (Jul 27, 2020)

noozi said:


> The zone that is having issues takes a few seconds each time it starts to re-pressurize and get the air out (I don't think that's a major issue) but seems to run well when it is going.


Hopefully each body has a check valve. Air can get in the line if one of the lower-elevation check valves fail, allowing the water to flow from the higher sprinklers to the lowers (look for an overly wet sprinkler or watch to see if water keeps creeping out after you shut the zone off).

The other alternative is an underground leak. If a tree root has broken a pipe, it could allow air into the line after the water leaks out and if the leak is significant, can reduce your water to that sprinkler. Any random wet spots around the yard?


----------



## Justmatson (Apr 4, 2020)

RVAGuy said:


> noozi said:
> 
> 
> > The zone that is having issues takes a few seconds each time it starts to re-pressurize and get the air out (I don't think that's a major issue) but seems to run well when it is going.
> ...


When I purchased 9 rotors from an online source I later found out some we're missing the screen/ check valve. 
Took me a while to figure out why 2 of my 3 zones were having low head drainage even though all 3 zones are identical in grade. 
Thats how I found out, water continued to pour out of the lowest head after the zone was off.


----------

