There could be multiple reasons you are not getting enough pressure at your sprinkler heads. The pump may need adjustment or may be shot all together. Did you check the pressure at the discharge on the pump? What is the capacity of the pump and what size is it? When was the last time the sprinklers operated normally? You might also check these "knob" valves to make sure they are operating properly and opening all the way, so as not to restrict water flow. It is also possible that there is some type of obstruction or a leak in the line if you are only getting low pressure on some zones but not others.
Tony Posey
Ridge Run Landscapes
