One of the most common reasons for a valve to keep running continuously is the accumulation of debris in the diaphragm, which prevents the valve from closing. This video will teach you how to clean the diaphragm on your valve.
The most common reason for a valve to remain on, or weep, is debris. New installations without proper flushing, recent mainline repair, or well water can cause debris to flow into the valve and get caught between the diaphragm and the seat.
It's also possible that there is debris in the valve, which is causing the diaphragm of the valve to remain open.
Issue: A tear in the internal part called the diaphragm would cause the valve not to close.
Solution: Dissaasemble the valve and inspect the internal parts.
It's possible your valves have been opened manually. You'll need to locate your valve box(s) and turn the solenoid(s) clockwise until snug. The solenoid is located on the top of the valve and looks like a cylinder with two wires protruding out of it.
Hunter valves require at least 20 PSI to close.
24 VAC solenoid
Issue: The bleed screw on the top of the valve might be loose or open.
Solution: Handtighten the bleed screw.
Issue: The valve is installed backward, which would be the opposite of the necessary flow direction.
Solution: Reinstall the valve. The arrow on the valve should be directed toward the sprinkler heads in the correct flow direction.