MP Rotator Cleaning/Maintenance


LawnSite Member

I have had MP Rotators installed in the yard for about three years now. There are 138 of them each paired with the MPR-40 sprinkler body with the 4" pop up. Water comes from a bore. There are 25 stations on 2 controllers and there are disc filters before each rank of valves.

I've never had a blockage on a rotator and I clean the disc filters (8) every three months or so. There have been times where the algae buildup has been so heavy that I have had to clean the filters more often and a couple of times throw a chemical down the bore hole to deal with the algae problem but generally it is okay. The algae tends to build up when the pump has been relatively inactive. I've never noticed any debri in the filter attached to the rotator itself.

Over the past 6 months or so, I've noticed a few rotators stop rotating. The problem might be first noticed by the grass dying off around the area of the problem rotator or one just notices the spray is fixed.

Has anyone had this problem before?. Is there a way to repair the problem rotator or is it a matter of replacing it?. Any other tips? Thanks :)



LawnSite Fanatic
District 9 CA
Check for debris and deposits under the top of the nozzle (the interior circle that pops up). I had one yesterday that stopped rotating, but was nothing more than a small piece of wood that had worked its way under that part of the nozzle. Sometimes you can "flush" out that section by pushing down on that part of the nozzle while the system is running. Also move the adjustment right through the full range. Other than that, sometimes they just stop rotating and you need to replace them.


LawnSite Senior Member
I have taken the MP out of my installations on pump systems because of this. They are not good for dirty water applications. They even foul up on city hook ups some times. If I were you I would slowly start changing out (Zone by Zone) the MP's for PGPs or RB 5004's.

You might also start using a more fine filter, this could help. I helped a guy out that has a system like yours before, and we changed the zone furthest from the pump from MPs to PGPs and ran that zone first. This helped "flush" the system main line out before the MP zones started. It was not a cure all, but it helped.

Just a thought.


LawnSite Member
Austin, Texas
We just finished putting in over 18,000 of these at the UT campus. I have learned that if there is any mineral in the water, that the MP filters will clog fast without sufficient filters .
Another problem that you may have if a lot of them are clogging right now is a small break on one of your lines. If all your zones are having the problem, may want to make sure that you do not have a minor break on your mainline. We came across this problem when a whole zone became clogged within in a few weeks. A small break happened on the lateral line and the area surrounding the break was sand. Well now all the zones in that area are full of sand. Took a while to find the minor break in a bed of ivy but fixed the problem.


LawnSite Fanatic
MPs are a fickle thing. They also tend to spin very fast when winterizing, once the water is pushed out. I don't know if that is going to be a future problem or not, with early failure.

Mike Leary

LawnSite Fanatic
It would have been nice if Walla Walla had us test the prototype more. I would have suggested the filter be removable, as it's big brother, the Stream Rotor could. All in all, though, they're a damn cool head.

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