Field notes
Why won't one of my sprinkler zones turn on?
Usually a failed valve solenoid, a cut or loose wire, or debris in the valve. Less often the zone was simply left out of the controller program. One zone dead while the others run points to that zone's valve or wiring.
When every zone but one runs, the controller is usually fine and the problem is that zone’s valve or the wire to it. These are the causes we find most often, from most to least common:
- Failed solenoid. The solenoid is the small electric part on top of the valve that opens it. They wear out, and a bad one keeps the valve closed. It’s a common, inexpensive replacement.
- Cut or loose wire. Edging, aeration, a fence post, or a new bed can nick the wire between the controller and the valve. Corroded splices in the valve box do the same thing.
- Debris in the valve. Grit from a main line repair can lodge in the valve and stop it from opening.
- The program. A zone with no run time, or one left off after a power outage or a controller change, never starts. This one is free to fix.
What you can check yourself: make sure the zone has a run time in the controller, then start it manually from the controller. If it still doesn’t run, the cause is almost always in the valve box or the wiring.
That’s where a licensed irrigator comes in. We test the wire and solenoid with a meter, find cut wires without digging up the yard, and fix the valve so the zone runs on schedule again.