pop up sprinkler

i bought a house with a real simple irrigation system installed.i replace one of the heads (after running it over with the lawnmower),and the system works good for about 3 minutes then the pressure drops to almost nothing.it seems to me that theres not enough pressure in the system.its strange ,it worked fine before,but i got the same head any tips would be appreciated

I'm still waiting to see if anyone is gonna give this guy a little help... I like to learn too and get other's opinions before I make an idiot out of myself.....

Replacing a broken sprinkler head with the same head should not cause your pressure to go down, unless the tee is also broken or there's another leak somewhere in the system.

However, none of this would explain why it works okay for 3 minutes and then stops working. Your zone valve may have to be cleaned out, or maybe your clock is malfunctioning, if you have one.

Another possibility is that you got dirt or rocks in the line when you changed out the broken head. Somehow, this debris keeps clogging and then uncloging the line. Take off the new head and open the valve to clean out the line. Put the head back on and see if the pressure still drops after 3 minutes. If it does, then the problem is probably in the valve, and you'll need to take it apart and clean it out.

What happens if you take off that sprinkler head and cap it off?

i cant really do anything now because of the frozen ground but i will flush the system out in the spring.My system is very basic.One line off main water supply to a ball valve then just pvc pipe out to just 4 heads.i have a small yard about 30 feet by 30 feet.Capping it iff sounds like a good idea too,mabye it will help narrow down the prob..It is just strange that it works 4 a couple mminutes and then it just piddles and the pump is still going fulll bore.Like i said when the ground thaws i will try your suggestions and let you fellas know how i did.Thanks for your help!

Was the water supply to your pump fully opened?

What is the pressure at the pump when this happens and what is the pressure otherwise?

bob..