Low Pressue and possible leak??
I ran an experiment on the system. I turned the main valve on as far as it would go (in the basement), heard the water gush. I then ran upstairs and turned all the valves on at the outside wall open as far as they would go. All the sprinkler heads worked, however, the pressure was extremely low. There was about a two feet of diameter spray from zone 1, 2 and 3 and zone 4 (the furtherest away) was all but a leak in the ground.
I turned off all the zones except for zone 1 and the water pressure was back up to normal spray (like it was before), this only happens when I turn everything else off though. Zone 1 and 2 seem to cover the majority of the lawn.