Locate the black flow control screw on the head of the valve and turn it clockwise with a screwdriver until you completely close the valve.
Turn on the water supply to the irrigation system via the water shut-off valve.
Turn the manual bleeder valve screw counterclockwise. This allows excess water to bleed back into the valve while you adjust the pressure in the valve.
Adjust the flow control screw until you are happy with the water pressure coming out of the irrigation valve.
Turn the manual bleeder valve screw clockwise, which will turn off the valve.