Water pressure lifts the nozzle mechanism of your sprinkler heads above ground level when the water is running. Normally, the nozzle will retract into the body of the sprinkler head where it is safe from damage by the lawnmower or playing children. Occasionally, dirt or grass clippings will find their way inside of the body and impede the nozzle from dropping back into the head. If the problem is addressed quickly, the debris can be cleaned and the sprinkler restored to use before further damage can occur.
Unscrew the cover from the sprinkler head. Remove the nozzle and spring assembly from the body of the sprinkler head.
Clean any debris from inside of the body or on the nozzle mechanism. Wash the components with water and wipe them down with a rag. If sand has become embedded in the plastic of the sprinkler body or nozzle it is advisable to replace the component rather than trying to clean it. The scratches and holes may lead to leaks during continued use.
Turn the water on to the irrigation circuit controlling the sprinkler head. This will force out any dirt or sand that might be the cause of repeated sticking after reassembly.
Spray the nozzle mechanism and spring with spray lubricant before reinserting it into the head. Screw the cover back onto the sprinkler to secure the nozzle.