Symptoms
- Controller display is blank or flashing
- Programmed watering times don't trigger
- Manual start works but scheduled runs don't
Likely causes
- CommonPower outage or unplugged transformer resetting the clockMany controllers lose their time/date setting after a power interruption without a backup battery.
- CommonDead backup batteryBackup batteries maintain settings during outages and need periodic replacement.
- PossibleRain sensor or smart sensor blocking the scheduleA stuck or malfunctioning rain sensor can prevent all zones from running even when it's dry.
- PossibleProgram settings accidentally changed or clearedA power surge or accidental button press can corrupt saved programs.
What to do
- Check that the transformer is plugged into a working outlet and the outlet itself has power.
- Verify the current time and date on the controller display are correct; reset if wrong.
- Replace the backup battery inside the controller if it hasn't been changed recently.
- Check if a rain or moisture sensor is connected and currently reading wet, which would legitimately pause watering.
- Re-enter your watering program, including start times, run durations, and days, in case settings were lost.
- If the controller won't hold settings even after these steps, the control board itself may need replacement.
Tools and parts
- Replacement battery (per controller model)
- Screwdriver (if opening the controller)
Sprinkler controller backup batterySearch: “irrigation controller backup battery”
Sprinkler controller replacementSearch: “irrigation sprinkler controller”
When to call a pro
An irrigation technician can replace a failed controller and reprogram zones correctly if you're unsure how your system is configured.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.