low pressure 1 zone

[babymern]

We moved into this house with sprinkler system in place last July. The sprinklers all worked great until the end of last summer when we noticed the first zone seemed to lose a lot of pressure. All of the other zones work great. I don't see any wet spots like there is a break in the line. We had a broken head on another line with water shooting straight up and the rest of the sprinklers in that zone still had good water pressure, so I think it takes a lot to lose pressure. I removed the solonoid (sp?) and ran the zone manually, but still had poor pressure. Any ideas?

[shag_fu]

Check pressure at the solenoid. Then start closing off the heads one at a time. Sometimes it takes a while for an underground leak to show up. If you close all the heads in that zone and turn on the solenoid you might get enough pressure to force the water to the surface more quickly. Might also attach a pressure gauge at the solenoid to see if the zone supply will hold pressure with the heads off. Then check at one of the heads with the others turned off to see if the zone itself is holding pressure.