Question
In one of the zones in  my lawn irrigation system only one of the sprinkler heads, out of 7 ,  is functioning with  a normal spray . It appears that the others do not have enough water pressure and are not producing a suffienct spray from the heads to provide adequate coverage. Where  should I start to look to see what the problem may be ?

Thank you.
Dave  

Answer
Start by adjusting the valve for that zone.  On top of the valve is a knob that controls the flow.  Open it all the way, then close it all the way counting the turns, then open it back half way.  If this doesn't work, you may need to dissemble the valve and clean out the "guts".  Sometimes it just as easy to replace the whole valve.  Also, make sure your wire connections are good.