I'm not an irrigation contractor. Besides minor/routine repair and maintenance, I refer out most irrigation installs and repair but I'm having a problem I thought I'd throw out here. Started a clients irrigation system yesterday. All zones are running but they've got very little pressure running through them. The main water valve is fully open and valves on the backflow device or fully open. There's no break in the main line because the water meter (irrigation system has it own meter) isn't running when the system is off. I did notice that one of the zone valves was making a pretty severe vibrating sound when in operation. Any ideas what could be causing the problem? Something I can fix or should I just call my irrigation guy?