Where to start, so many things make a zone stick on.

Most likely is the control valve itself on zone 13 is either manually activated in the valve box, or there is debris in the valve.

Less likely is the solenoid (the thing on top of the valve with the two wires) has a hung up plunger, or the controller is sending out voltage to zone 13 all the time (very improbable)

Make sure all the plastic bleed screws and solenoids on the four valves are righty tighty finger tight.

This may shut off the zone if it is manually activated.

If not, determine which valve controls zone 13 by either manually bleeding each valve until only the stuck one runs, or by looking at the zone 13 terminal screw in the controller and make note of the color of the wire connected to that terminal, and the corresponding solenoid of the offending valve should have one of the two wires hooked to that color if you have multistranded colored wire.

If it is still stuck, you'll need to turn off the water and take the valve apart to look for any debris. There should either be 6 screws in the top of the valve, or it should have a 'jar' top, where the top ring will unscrew from the valve. either way take it apart, clean it out if need be, and reassemble diaphragm first, spring, then top.

Turn the water on and see if it stays off. If not it will be a little more involved, let me know.

Tom

There was debris in the valve. Thanks alot for your help Tom.