Lawn Sprinkler Troubleshooting

[NamPhong]

Long time lurker that now needs assistance with lawn sprinklers. Turned them on about 1 week ago and all zones but one work. That zone when turned on does not cause any heads to pop up and only a trickle of water comes from each head. We have had a lot of rain (southeast Nebraska) so the ground is already wet which keeps me from letting the system run and spotting any leak. I am no artist but the diagram sort of represents the zone I am having trouble with.

| | o o | | | | o o | | | | _______ O O | Valve| | | | Box |________________|_______________________| ________ o o | | | | o o

Any tips on finding/isolating the problem before the weather turns really dry would be greatly appreciated.

Thanks for any help and will post the results of the repair once the problem is found.

[NamPhong]

Crappy newsreader but here are answers to questions asked.

Did manually operate valve for that zone and the results were the same.

Yes, we are in freezing area and lines were blown out in the fall.

[gfretwell]

On a sprinkler line it would plug up in a week or two. I have a 150 gallon aerator tank and that will get a 1/2" of sand in it in 6 months.

[NamPhong]

Still rain falling almost every day so have not had a chance to do much. Appreciate all of the hints and once/if ground starts to dry will start using them.