There is rocks or something in the valve that came in from water sorce (meter) turn water off unscrew screws on valve remove top ,remove object(s) from inside valve and replace ,turn water on and test if still stays on screw down water control Flow on top of valve clockwise slowly till it shuts down .
Nestor's Sprinklers & Lighting Alpharetta,Ga 770/410-9356
vincent nestor
Vincent Nestor
Nestor's Sprinklers & Lighting
Alpharetta,Ga.30022
vpn1@bellsouth.net
www.NestorsLandScape.com
www.GeorgiaLighting.net