I am having problems with 1 of the 4 zones on my sprinkler system.We moved into a new home with an existing sprinkler system about 3 years ago.The first year the system worked fine.Last year everything started up fine in the spring but suddenly one of the zones stopped working.We replaced the valve thinking that it was bad and after screwing around with it for hours the zone came on.It ran for about 1 minute and shut down.As it shut down the ground really started to vibrate.We ran into the same thing this spring(That zone came on once,ran for about a minute and shut down with the ground vibrating ).Any ideas as to what might be causing this?