If one zone will not come on and the others work fine, the problem is almost never the controller. It is the valve, the wiring to that valve, or the solenoid on top of it. Those three account for the large majority of dead-zone calls we take across Plano, Frisco, and McKinney.
Work through the checks below in order. Two of them you can do yourself in ten minutes, and they will tell you whether this is a twenty dollar part or a real repair.
Start by proving it is not the controller
Run the zone manually from the controller. If it still will not start, try running a different zone from the same controller. If the other zone runs, the controller is fine and the fault is downstream in that specific zone.
If no zone runs at all, check the transformer and that the controller has power. A surprising number of no-water calls in DFW turn out to be a tripped GFCI in the garage.
The five usual causes, in order of likelihood
Once you know it is one zone only, it is nearly always one of these.
- A failed solenoid. The small cylinder on top of the valve. It clicks when it works and it is the single most common failure.
- A wiring break between the controller and the valve. Common where the wire crosses a bed that has been dug in.
- Grit inside the valve, which stops it opening or only lets it open partway.
- A shut-off valve left closed or half closed, sometimes after other work in the yard.
- A cracked lateral line downstream, which drops pressure so far that heads never pop up.
The one test worth doing yourself
Find the valve box for the dead zone and manually open the valve by turning the small bleed screw a quarter turn counter-clockwise, or by twisting the solenoid a quarter turn.
If water flows and the heads pop up, the valve and the pipe are fine and your problem is electrical, meaning the solenoid or the wire. If nothing happens with the valve manually open, the problem is on the water side: a stuck valve, a shut-off left closed, or a break in the line.
That single test splits the diagnosis in half, and it is the first thing a good tech will do when they arrive.
What this costs to fix in DFW
Most single-zone faults are inexpensive once diagnosed. The cost is in finding it, not fixing it.
| Fault | Typical repair cost |
|---|---|
| Solenoid replacement | $75 to $175 |
| Valve replacement | $175 to $350 |
| Wiring fault trace and repair | $150 to $400 |
| Lateral line break | $250 to $600 |
| Diagnostic visit | $75 to $150, often credited |
Texas requires a licensed irrigator
This part matters. In Texas, installing, altering, or repairing an irrigation system for compensation requires a licensed irrigator, and that licensed irrigator also signs off on the backflow device protecting your drinking water.
You can replace your own heads on your own property. Anyone you pay to do valve, wiring, or line work should be able to give you a license number, and you can verify it. A quote that is dramatically cheaper than the rest is usually cheaper because of this.
Key takeaways
- One dead zone with the others working means the fault is that zone's valve, solenoid, or wiring, not the controller
- Manually opening the valve splits the diagnosis: water flows means electrical, no water means the valve or the line
- A tripped GFCI in the garage explains a surprising number of no-water calls
- Most single-zone repairs land between $75 and $400 once the cause is known
- Paid irrigation repair in Texas requires a licensed irrigator, so ask for the number
Sources
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