I have one zone on a 6 zone clock which will not run for the allotted time. I have switched the wiring from one zone on the clock to another and that did not change anything. I have switched things around until the only thing that remains the same is the zone valve. Why would a zone valve shut off after 2 or 3 minutes when it is scheduled for 20. This is an older system that has been working properly until recently.
Thanks for your help.
If the controller is sending power to the valve, and the valve stops operating, there may be a short circuit that is cutting off the watering. These don't always behave instantaneously.